diff --git a/.github/workflows/ci_windows_mingw.yml b/.github/workflows/ci_windows_mingw.yml
index 7f6b64f..e4feeb9 100644
--- a/.github/workflows/ci_windows_mingw.yml
+++ b/.github/workflows/ci_windows_mingw.yml
@@ -1,79 +1,79 @@
-name: CI Windows Mingw
-
-on:
-  push:
-    branches: [ master ]
-  pull_request:
-    branches: [ master ]
-
-  workflow_dispatch:
-
-env:
-  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
-  BUILD_TYPE: RELWITHDEBINFO
-
-jobs:
-
-
-  win-build:
-    runs-on: windows-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - { icon: '⬛', sys: mingw32, env: i686 }
-          - { icon: '🟦', sys: mingw64, env: x86_64 }
-          - { icon: '🟨', sys: ucrt64,  env: ucrt-x86_64 }  # Experimental!
-#          - { icon: '🟧', sys: clang64, env: clang-x86_64 } # Experimental!
-    name: 🚧${{ matrix.icon }}-${{ matrix.sys }}
-    defaults:
-      run:
-        shell: msys2 {0}
-    env:
-      MINGW_ARCH: ${{ matrix.sys }}
-    steps:
-
-    - name: '⚙️ git config'
-      run: git config --global core.autocrlf input
-      shell: bash
-
-    - name: '🧰 Checkout'
-      uses: actions/checkout@v2
-      with:
-        fetch-depth: 0
-
-    - name: '${{ matrix.icon }} Setup MSYS2'
-      uses: msys2/setup-msys2@v2
-      with:
-        msystem: ${{ matrix.sys }}
-        update: true
-        install: >
-          git
-          base-devel
-          tree
-          mingw-w64-${{ matrix.env }}-toolchain
-          mingw-w64-${{ matrix.env }}-libpng
-          mingw-w64-${{ matrix.env }}-libjpeg-turbo
-          mingw-w64-${{ matrix.env }}-freetype
-          mingw-w64-${{ matrix.env }}-libtiff
-          mingw-w64-${{ matrix.env }}-libwebp
-          mingw-w64-${{ matrix.env }}-libheif
-          mingw-w64-${{ matrix.env }}-libraqm
-          mingw-w64-${{ matrix.env }}-libimagequant
-          mingw-w64-${{ matrix.env }}-libavif
-          mingw-w64-${{ matrix.env }}-cmake
-
-    - name: '🚧 Cmake Configure'
-      run:  |
-          MSYSTEM=MINGW64 cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Debug -DENABLE_PNG=1  -DENABLE_FREETYPE=1 -DENABLE_XPM=0 -DENABLE_JPEG=1 -DENABLE_WEBP=0 -DENABLE_TIFF=1  -DENABLE_XPM=0 -DENABLE_GD_FORMATS=1 -DENABLE_HEIF=1 -DENABLE_RAQM=1 -DBUILD_TEST=1 -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}} -B.
-
-    - name: Build
-      run: cmake --build . --config ${{env.BUILD_TYPE}} --parallel 4
-
-    - name: Run tests
-      working-directory: ${{github.workspace}}
-      run: |
-        mkdir tmp
-        export TMP=${{github.workspace}}\\tmp
-        export CTEST_OUTPUT_ON_FAILURE=1
-        ctest -C ${{env.BUILD_TYPE}}
+name: CI Windows Mingw
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+  workflow_dispatch:
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: RELWITHDEBINFO
+
+jobs:
+
+
+  win-build:
+    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - { icon: '⬛', sys: mingw32, env: i686 }
+          - { icon: '🟦', sys: mingw64, env: x86_64 }
+          - { icon: '🟨', sys: ucrt64,  env: ucrt-x86_64 }  # Experimental!
+#          - { icon: '🟧', sys: clang64, env: clang-x86_64 } # Experimental!
+    name: 🚧${{ matrix.icon }}-${{ matrix.sys }}
+    defaults:
+      run:
+        shell: msys2 {0}
+    env:
+      MINGW_ARCH: ${{ matrix.sys }}
+    steps:
+
+    - name: '⚙️ git config'
+      run: git config --global core.autocrlf input
+      shell: bash
+
+    - name: '🧰 Checkout'
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+
+    - name: '${{ matrix.icon }} Setup MSYS2'
+      uses: msys2/setup-msys2@v2
+      with:
+        msystem: ${{ matrix.sys }}
+        update: true
+        install: >
+          git
+          base-devel
+          tree
+          mingw-w64-${{ matrix.env }}-toolchain
+          mingw-w64-${{ matrix.env }}-libpng
+          mingw-w64-${{ matrix.env }}-libjpeg-turbo
+          mingw-w64-${{ matrix.env }}-freetype
+          mingw-w64-${{ matrix.env }}-libtiff
+          mingw-w64-${{ matrix.env }}-libwebp
+          mingw-w64-${{ matrix.env }}-libheif
+          mingw-w64-${{ matrix.env }}-libraqm
+          mingw-w64-${{ matrix.env }}-libimagequant
+          mingw-w64-${{ matrix.env }}-libavif
+          mingw-w64-${{ matrix.env }}-cmake
+
+    - name: '🚧 Cmake Configure'
+      run:  |
+          MSYSTEM=MINGW64 cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Debug -DENABLE_PNG=1  -DENABLE_FREETYPE=1 -DENABLE_XPM=0 -DENABLE_JPEG=1 -DENABLE_WEBP=0 -DENABLE_TIFF=1  -DENABLE_XPM=0 -DENABLE_GD_FORMATS=1 -DENABLE_HEIF=1 -DENABLE_RAQM=1 -DBUILD_TEST=1 -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}} -B.
+
+    - name: Build
+      run: cmake --build . --config ${{env.BUILD_TYPE}} --parallel 4
+
+    - name: Run tests
+      working-directory: ${{github.workspace}}
+      run: |
+        mkdir tmp
+        export TMP=${{github.workspace}}\\tmp
+        export CTEST_OUTPUT_ON_FAILURE=1
+        ctest -C ${{env.BUILD_TYPE}}
diff --git a/cmake/modules/linux-clang.cmake b/cmake/modules/linux-clang.cmake
index ab2114e..7cfc075 100644
--- a/cmake/modules/linux-clang.cmake
+++ b/cmake/modules/linux-clang.cmake
@@ -1,239 +1,239 @@
-# This file is part of the cmake-tools project. It was retrieved from
-# https://github.com/wang-bin/cmake-tools
-#
-# The cmake-tools project is licensed under the new MIT license.
-#
-# Copyright (c) 2017-2021, Wang Bin
-#
-# clang + lld to cross build apps for linux
-#
-# LINUX_FLAGS: flags for both compiler and linker, e.g. --target=arm-rpi-linux-gnueabihf ...
-# CMAKE_SYSTEM_PROCESSOR: REQUIRED
-# USE_CRT: gnu(default), musl
-
-option(CLANG_AS_LINKER "use clang as linker to invoke lld. MUST ON for now" ON)
-option(USE_LIBCXX "use libc++ instead of libstdc++" OFF)
-option(USE_CXXABI "can be c++abi, stdc++ and supc++. Only required if libc++ is built with none abi" OFF) # default value must be bool
-option(USE_TARGET_LIBCXX "libc++ headers bundled with clang are searched and used by default. usually safe if abi is stable. set to true to use target libc++ if version is different" OFF)
-option(USE_COMPILER_RT "use compiler-rt instead of libgcc as compiler runtime library" OFF)
-option(USE_STD_TLS "use std c++11 thread_local. Only libc++abi 4.0+ is safe for any libc runtime. Turned off internally when necessary" ON) # sunxi ubuntu12.04(glibc-2.15)/rpi(glibc2.13) libc is too old to have __cxa_thread_atexit_impl(requires glibc2.18)
-option(USE_STDCXX "libstdc++ version to use, MUST be >= 4.8. default is 0, selected by compiler" 0)
-
-if(NOT OS)
-  set(OS Linux)
-endif()
-set(CMAKE_SYSTEM_NAME Linux) # assume host build if not set, host flags will be used, e.g. apple clang flags are added on macOS
-if(NOT CMAKE_SYSTEM_PROCESSOR)
-  message("CMAKE_SYSTEM_PROCESSOR for target is not set. Must be aarch64(arm64), armv7(arm), x86(i386,i686), x64(x86_64). Assumeme build for host arch: ${CMAKE_HOST_SYSTEM_PROCESSOR}.")
-  set(CMAKE_SYSTEM_PROCESSOR ${CMAKE_HOST_SYSTEM_PROCESSOR})
-endif()
-if(CMAKE_SYSTEM_PROCESSOR MATCHES "ar.*64")
-  set(TRIPLE_ARCH aarch64)
-elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "arm") # arm.*hf?
-  set(TRIPLE_ARCH arm)
-  set(TRIPLE_ABI eabihf)
-elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "64")
-  set(TRIPLE_ARCH x86_64)
-elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "86")
-  set(TRIPLE_ARCH i386)
-endif()
-if(NOT USE_CRT) # can be gnu, musl
-  set(USE_CRT gnu)
-endif()
-set(TARGET_TRIPPLE ${TRIPLE_ARCH}-linux-${USE_CRT}${TRIPLE_ABI})
-set(LINUX_FLAGS "--target=${TARGET_TRIPPLE} ${LINUX_FLAGS}")
-
-set(CMAKE_LIBRARY_ARCHITECTURE ${TARGET_TRIPPLE}) # FIND_LIBRARY search subdir
-# "/usr/local/opt/llvm/bin/ld.lld" --sysroot=/Users/wangbin/dev/rpi/sysroot -pie -X --eh-frame-hdr -m armelf_linux_eabi -dynamic-linker /lib/ld-linux-armhf.so.3 -o test/audiodec /Users/wangbin/dev/rpi/sysroot/usr/lib/../lib/Scrt1.o /Users/wangbin/dev/rpi/sysroot/usr/lib/../lib/crti.o /Users/wangbin/dev/rpi/sysroot/lib/../lib/crtbeginS.o -L/Users/wangbin/dev/rpi/sysroot/lib/../lib -L/Users/wangbin/dev/rpi/sysroot/usr/lib/../lib -L/Users/wangbin/dev/rpi/sysroot/lib -L/Users/wangbin/dev/rpi/sysroot/usr/lib --build-id --as-needed --gc-sections --enable-new-dtags -z origin "-rpath=\$ORIGIN" "-rpath=\$ORIGIN/lib" -rpath-link /Users/wangbin/dev/multimedia/mdk/external/lib/rpi/armv6 test/CMakeFiles/audiodec.dir/audiodec.cpp.o libmdk.so.0.1.0 -lc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /Users/wangbin/dev/rpi/sysroot/lib/../lib/crtendS.o /Users/wangbin/dev/rpi/sysroot/usr/lib/../lib/crtn.o
-
-# Export configurable variables for the try_compile() command. Or set env var like llvm
-set(CMAKE_TRY_COMPILE_PLATFORM_VARIABLES
-  CMAKE_SYSTEM_PROCESSOR
-  CMAKE_C_COMPILER # find_program only once
-  LINUX_FLAGS
-  #LINUX_SYSROOT
-  LD_LLD
-)
-
-if(NOT CMAKE_C_COMPILER)
-  find_program(CMAKE_C_COMPILER clang-12 clang-11 clang-10 clang-9 clang-8 clang-7 clang-6.0 clang-5.0 clang-4.0 clang
-    HINTS /usr/local/opt/llvm/bin
-    CMAKE_FIND_ROOT_PATH_BOTH
-  )
-endif()
-
-if(CMAKE_C_COMPILER)
-  if(NOT CMAKE_CXX_COMPILER)
-    string(REGEX REPLACE "clang(|-[0-9]+[\\.0]*)$" "clang++\\1" CMAKE_CXX_COMPILER "${CMAKE_C_COMPILER}")
-    if(NOT EXISTS "${CMAKE_CXX_COMPILER}") # homebrew, clang-6.0 but clang++ has no suffix
-      string(REGEX REPLACE "clang(|-[0-9]+[\\.0]*)$" "clang++" CMAKE_CXX_COMPILER "${CMAKE_C_COMPILER}")
-    endif()
-  endif()
-  if(NOT LD_LLD)
-    string(REGEX REPLACE ".*clang(|-[0-9]+[\\.0]*)$" "lld\\1" LD_LLD "${CMAKE_C_COMPILER}")
-    execute_process(
-      COMMAND ${CMAKE_C_COMPILER} -print-prog-name=${LD_LLD}
-      OUTPUT_VARIABLE LD_LLD_PATH
-      OUTPUT_STRIP_TRAILING_WHITESPACE
-    )
-    if(NOT EXISTS ${LD_LLD_PATH}) # llvm on macOS(via brew) has lld but not lld-?
-      set(LD_LLD lld)
-    endif()
-  endif()
-else()
-  set(CMAKE_C_COMPILER clang)
-  set(CMAKE_CXX_COMPILER clang++)
-  set(LD_LLD lld)
-endif()
-
-# llvm-ranlib is for bitcode. but seems works for others. "llvm-ar -s" should be better
-# macOS system ranlib does not work
-execute_process(
-  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-ranlib
-  OUTPUT_VARIABLE CMAKE_RANLIB
-  OUTPUT_STRIP_TRAILING_WHITESPACE
-)
-# llvm-ar for all host platforms. support all kinds of file, including bitcode
-execute_process(
-  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-ar
-  OUTPUT_VARIABLE CMAKE_LLVM_AR
-  OUTPUT_STRIP_TRAILING_WHITESPACE
-)
-execute_process(
-  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-readelf
-  OUTPUT_VARIABLE READELF
-  OUTPUT_STRIP_TRAILING_WHITESPACE
-)
-execute_process(
-  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-objcopy
-  OUTPUT_VARIABLE CMAKE_LLVM_OBJCOPY
-  OUTPUT_STRIP_TRAILING_WHITESPACE
-)
-get_filename_component(LLVM_DIR ${CMAKE_RANLIB} DIRECTORY)
-
-# Sysroot.
-#message("CMAKE_SYSROOT_COMPILE: ${CMAKE_SYSROOT_COMPILE}, ${CMAKE_CROSSCOMPILING}")
-if(EXISTS "${LINUX_SYSROOT}")
-  set(CMAKE_SYSROOT ${LINUX_SYSROOT})
-# CMake 3.9 tries to use CMAKE_SYSROOT_COMPILE before it gets set from CMAKE_SYSROOT, which leads to using the system's /usr/include. Set this manually.
-# https://github.com/android-ndk/ndk/issues/467
-  set(CMAKE_SYSROOT_COMPILE "${CMAKE_SYSROOT}")
-endif()
-if(CMAKE_CROSSCOMPILING) # default is true
-  set(ENV{PKG_CONFIG_PATH} "${CMAKE_SYSROOT}/usr/share/pkgconfig:${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPPLE}/pkgconfig")
-endif()
-set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
-set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
-set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
-set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
-
-if(USE_LIBCXX)
-  if(CMAKE_CROSSCOMPILING AND USE_TARGET_LIBCXX) # assume libc++ abi is stable, then USE_TARGET_LIBCXX=0 is ok, i.e. build with host libc++, but run with a different target libc++ version
-  # headers in clang builtin include dir(stddef.h etc.). -nobuiltininc makes cross build harder if a header is not found in sysroot(include_next stddef.h in /usr/include/linux/)
-    # -nostdinc++: clang always search libc++(-stdlib=libc++) in host toolchain, may mismatch with target libc++ version, and results in conflict(include_next)
-    if(CMAKE_VERSION VERSION_LESS 3.3)
-      set(LINUX_FLAGS_CXX "${LINUX_FLAGS_CXX} -nostdinc++ -iwithsysroot /usr/include/c++/v1")
-    else()
-      #add_compile_options("$<$<COMPILE_LANGUAGE:CXX>:-stdlib=libc++>")
-      add_compile_options("$<$<COMPILE_LANGUAGE:CXX>:-nostdinc++;-iwithsysroot;/usr/include/c++/v1>")
-    endif()
-    # -stdlib=libc++ is not required if -nostdinc++ is set(otherwise warnings)
-    link_libraries(-stdlib=libc++) #unlike SUNXI_LD_FLAGS, it will append flags to last
-  else()
-    set(LINUX_FLAGS_CXX "${LINUX_FLAGS_CXX} -stdlib=libc++") # for both compiler & linker
-  endif()
-  if(USE_CXXABI)
-    set(LINUX_LINK_FLAGS_CXX "${LINUX_LINK_FLAGS_CXX} -l${USE_CXXABI}") # required if libc++ is built with none abi. otherwise libc++.so is a ld script contains an abi library, e.g. -lc++abi/-lstdc++/-lsupc++
-  endif()
-  #check_library_exists:  compiler must be detected
-  # old libc + old libc++abi: DO NOT use thread_local
-  # new/old libc + new libc++abi: use libc++abi tls/fallback
-  # new libc + old libc++abi: can not ensure libc runtime thread_local support
-  # old libc + stdc++ abi: disable thread_local, stdc++(g++8.0) does not use __cxa_thread_atexit_impl as weak symbol, so can not run on old glibc runtime
-  set(LIBCXX_SO "${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPPLE}/libc++.so.1")
-  if(EXISTS ${LIBCXX_SO})
-    execute_process(
-      COMMAND ${READELF} -needed-libs ${LIBCXX_SO}
-      OUTPUT_VARIABLE LIBCXX_NEEDED
-      OUTPUT_STRIP_TRAILING_WHITESPACE
-    )
-    string(FIND "${LIBCXX_NEEDED}" libc++abi.so.1 LIBCXX_ABI_LIBCXXABI) # TODO: built with static libc++abi, check exported abi symbols
-    if(LIBCXX_ABI_LIBCXXABI EQUAL -1)
-      #message("libc++ is not built with libc++abi. not safe to use thread_local on old libstdc++ runtime for libc++<7.0")
-      #set(USE_STD_TLS OFF)
-    else()
-      set(LIBCXXABI_SO "${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPPLE}/libc++abi.so.1") #LIST_DIRECTORIES must be true (false by default for GLOB_RECURSE)
-      if(EXISTS ${LIBCXXABI_SO})
-        execute_process(
-          COMMAND ${READELF} -symbols ${LIBCXXABI_SO}
-          OUTPUT_VARIABLE LIBCXXABI_SYMBOLS
-          OUTPUT_STRIP_TRAILING_WHITESPACE
-        )
-        string(REGEX MATCH "WEAK [A-Z ]* __cxa_thread_atexit_impl" WEAK__cxa_thread_atexit_impl "${LIBCXXABI_SYMBOLS}")
-        string(REGEX MATCH "GLOBAL [A-Z ]* __cxa_thread_atexit_impl" __cxa_thread_atexit_impl "${LIBCXXABI_SYMBOLS}") # UND __cxa_thread_atexit_impl@GLIBC_2.18
-        if(NOT WEAK__cxa_thread_atexit_impl AND NOT __cxa_thread_atexit_impl)
-          message("libc++abi in build environment is too old to support thread_local on old libc runtime")
-          #set(USE_STD_TLS OFF)
-        endif()
-      endif()
-    endif()
-  endif()
-  set(LIBC_SO "${CMAKE_SYSROOT}/lib/${TARGET_TRIPPLE}/libc.so.6")
-  execute_process(
-    COMMAND ${READELF} -symbols ${LIBC_SO}
-    OUTPUT_VARIABLE LIBC_SYMBOLS
-    OUTPUT_STRIP_TRAILING_WHITESPACE
-  )
-  string(FIND "${LIBC_SYMBOLS}" __cxa_thread_atexit_impl HAS__cxa_thread_atexit_impl)
-  if(HAS__cxa_thread_atexit_impl EQUAL -1 AND NOT WEAK__cxa_thread_atexit_impl) # old libc + stdc++/libc++abi<4.0
-    # libc++abi 4.0+ check use __cxa_thread_atexit_impl as weak symbol, and can fallback to libc++ own implementation
-    message(STATUS "libc in build environment is too old to support C++11 thread_local without libc++abi 4.0+")
-    set(USE_STD_TLS OFF)
-  endif()
-  #if(USE_STD_TLS AND NOT HAS__cxa_thread_atexit_impl EQUAL -1) # AND c++abi is none or libc++abi<4.0, then __cxa_thread_atexit generated by clang(for thread_local) can be replaced by __cxa_thread_atexit_impl
-  #  link_libraries(-Wl,-defsym,__cxa_thread_atexit=__cxa_thread_atexit_impl) # libc++ abi is not libc++abi, e.g. stdc++/supc++ abi. clang generated __cxa_thread_atexit is defined in libc++abi 4.0+
-  #endif()
-else() # gcc files can be found by clang
-  if(NOT USE_STDCXX VERSION_LESS 4.8)
-  # Selected GCC installation: always the last (greatest version), no way to change it
-    add_compile_options(-nostdinc++)
-    #file(GLOB_RECURSE CXX_DIRS LIST_DIRECTORIES true "${CMAKE_SYSROOT}/usr/include/*c++") # c++ is dir, so LIST_DIRECTORIES must be true (false by default for GLOB_RECURSE)
-    add_compile_options("-cxx-isystem${CMAKE_SYSROOT}/usr/include/c++/${USE_STDCXX}") # no space after -cxx-isystem
-    add_compile_options("-cxx-isystem${CMAKE_SYSROOT}/usr/include/${TARGET_TRIPPLE}/c++/${USE_STDCXX}") # no space after -cxx-isystem
-  endif()
-endif()
-
-if(CLANG_AS_LINKER)
-  link_libraries(-Wl,--build-id -fuse-ld=${LD_LLD}) # -s: strip
-  if(USE_COMPILER_RT)
-    link_libraries(-rtlib=compiler-rt)
-  endif()
-else()
-  #set(CMAKE_LINER      "${LD_LLD}" CACHE INTERNAL "linker" FORCE)
-  set(LINUX_LD_FLAGS "${LINUX_LD_FLAGS} --build-id --sysroot=${CMAKE_SYSROOT}") # -s: strip
-  macro(set_cc_clang lang)
-    set(CMAKE_${lang}_LINK_EXECUTABLE
-        "<CMAKE_LINKER> -flavor gnu <CMAKE_${lang}_LINK_FLAGS> <LINK_FLAGS> <LINK_LIBRARIES> <OBJECTS> -o <TARGET>")
-    set(CMAKE_${lang}_CREATE_SHARED_LIBRARY
-        "<CMAKE_LINKER> -flavor gnu <CMAKE_${lang}_LINK_FLAGS> <CMAKE_SHARED_LIBRARY_${lang}_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
-    set(CMAKE_${lang}_CREATE_SHARED_MODULE
-        "<CMAKE_LINKER> -flavor gnu <CMAKE_${lang}_LINK_FLAGS> <CMAKE_SHARED_MODULE_${lang}_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
-  endmacro()
-  set_cc_clang(C)
-  set_cc_clang(CXX)
-endif()
-#53472, 5702912
-# Set or retrieve the cached flags. Without these compiler probing may fail!
-
-set(CMAKE_AR         "${CMAKE_LLVM_AR}" CACHE INTERNAL "${CMAKE_SYSTEM_NAME} ar" FORCE)
-set(CMAKE_OBJCOPY    "${CMAKE_LLVM_OBJCOPY}" CACHE INTERNAL "${CMAKE_SYSTEM_NAME} objcopy" FORCE)
-set(CMAKE_C_FLAGS    "${LINUX_FLAGS}" CACHE INTERNAL "${CMAKE_SYSTEM_NAME} c compiler flags" FORCE)
-set(CMAKE_CXX_FLAGS  "${LINUX_FLAGS} ${LINUX_FLAGS_CXX}"  CACHE INTERNAL "${CMAKE_SYSTEM_NAME} c++ compiler/linker flags" FORCE)
-set(CMAKE_ASM_FLAGS  "${LINUX_FLAGS}"  CACHE INTERNAL "${CMAKE_SYSTEM_NAME} asm compiler flags" FORCE)
-set(CMAKE_CXX_LINK_FLAGS "${LINUX_LINK_FLAGS_CXX}" CACHE INTERNAL "additional c++ link flags")
-set(LD_LLD "${LD_LLD}" CACHE INTERNAL "${LD_LLD} as linker" FORCE)
-# CMAKE_C_FLAGS_MINSIZEREL_INIT: will append -Os by cmake, which is not expected, and results in lto link error
-set(CMAKE_C_FLAGS_MINSIZEREL "-Xclang -Oz -DNDEBUG") # -Xclang is required because c/c++ flags is passed to linker and not recognized by linker(-O1/2 is ok, -Os/z is not)
-set(CMAKE_CXX_FLAGS_MINSIZEREL "-Xclang -Oz -DNDEBUG")
-
-set(CMAKE_BUILD_WITH_INSTALL_RPATH ON)
\ No newline at end of file
+# This file is part of the cmake-tools project. It was retrieved from
+# https://github.com/wang-bin/cmake-tools
+#
+# The cmake-tools project is licensed under the new MIT license.
+#
+# Copyright (c) 2017-2021, Wang Bin
+#
+# clang + lld to cross build apps for linux
+#
+# LINUX_FLAGS: flags for both compiler and linker, e.g. --target=arm-rpi-linux-gnueabihf ...
+# CMAKE_SYSTEM_PROCESSOR: REQUIRED
+# USE_CRT: gnu(default), musl
+
+option(CLANG_AS_LINKER "use clang as linker to invoke lld. MUST ON for now" ON)
+option(USE_LIBCXX "use libc++ instead of libstdc++" OFF)
+option(USE_CXXABI "can be c++abi, stdc++ and supc++. Only required if libc++ is built with none abi" OFF) # default value must be bool
+option(USE_TARGET_LIBCXX "libc++ headers bundled with clang are searched and used by default. usually safe if abi is stable. set to true to use target libc++ if version is different" OFF)
+option(USE_COMPILER_RT "use compiler-rt instead of libgcc as compiler runtime library" OFF)
+option(USE_STD_TLS "use std c++11 thread_local. Only libc++abi 4.0+ is safe for any libc runtime. Turned off internally when necessary" ON) # sunxi ubuntu12.04(glibc-2.15)/rpi(glibc2.13) libc is too old to have __cxa_thread_atexit_impl(requires glibc2.18)
+option(USE_STDCXX "libstdc++ version to use, MUST be >= 4.8. default is 0, selected by compiler" 0)
+
+if(NOT OS)
+  set(OS Linux)
+endif()
+set(CMAKE_SYSTEM_NAME Linux) # assume host build if not set, host flags will be used, e.g. apple clang flags are added on macOS
+if(NOT CMAKE_SYSTEM_PROCESSOR)
+  message("CMAKE_SYSTEM_PROCESSOR for target is not set. Must be aarch64(arm64), armv7(arm), x86(i386,i686), x64(x86_64). Assumeme build for host arch: ${CMAKE_HOST_SYSTEM_PROCESSOR}.")
+  set(CMAKE_SYSTEM_PROCESSOR ${CMAKE_HOST_SYSTEM_PROCESSOR})
+endif()
+if(CMAKE_SYSTEM_PROCESSOR MATCHES "ar.*64")
+  set(TRIPLE_ARCH aarch64)
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "arm") # arm.*hf?
+  set(TRIPLE_ARCH arm)
+  set(TRIPLE_ABI eabihf)
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "64")
+  set(TRIPLE_ARCH x86_64)
+elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "86")
+  set(TRIPLE_ARCH i386)
+endif()
+if(NOT USE_CRT) # can be gnu, musl
+  set(USE_CRT gnu)
+endif()
+set(TARGET_TRIPPLE ${TRIPLE_ARCH}-linux-${USE_CRT}${TRIPLE_ABI})
+set(LINUX_FLAGS "--target=${TARGET_TRIPPLE} ${LINUX_FLAGS}")
+
+set(CMAKE_LIBRARY_ARCHITECTURE ${TARGET_TRIPPLE}) # FIND_LIBRARY search subdir
+# "/usr/local/opt/llvm/bin/ld.lld" --sysroot=/Users/wangbin/dev/rpi/sysroot -pie -X --eh-frame-hdr -m armelf_linux_eabi -dynamic-linker /lib/ld-linux-armhf.so.3 -o test/audiodec /Users/wangbin/dev/rpi/sysroot/usr/lib/../lib/Scrt1.o /Users/wangbin/dev/rpi/sysroot/usr/lib/../lib/crti.o /Users/wangbin/dev/rpi/sysroot/lib/../lib/crtbeginS.o -L/Users/wangbin/dev/rpi/sysroot/lib/../lib -L/Users/wangbin/dev/rpi/sysroot/usr/lib/../lib -L/Users/wangbin/dev/rpi/sysroot/lib -L/Users/wangbin/dev/rpi/sysroot/usr/lib --build-id --as-needed --gc-sections --enable-new-dtags -z origin "-rpath=\$ORIGIN" "-rpath=\$ORIGIN/lib" -rpath-link /Users/wangbin/dev/multimedia/mdk/external/lib/rpi/armv6 test/CMakeFiles/audiodec.dir/audiodec.cpp.o libmdk.so.0.1.0 -lc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /Users/wangbin/dev/rpi/sysroot/lib/../lib/crtendS.o /Users/wangbin/dev/rpi/sysroot/usr/lib/../lib/crtn.o
+
+# Export configurable variables for the try_compile() command. Or set env var like llvm
+set(CMAKE_TRY_COMPILE_PLATFORM_VARIABLES
+  CMAKE_SYSTEM_PROCESSOR
+  CMAKE_C_COMPILER # find_program only once
+  LINUX_FLAGS
+  #LINUX_SYSROOT
+  LD_LLD
+)
+
+if(NOT CMAKE_C_COMPILER)
+  find_program(CMAKE_C_COMPILER clang-12 clang-11 clang-10 clang-9 clang-8 clang-7 clang-6.0 clang-5.0 clang-4.0 clang
+    HINTS /usr/local/opt/llvm/bin
+    CMAKE_FIND_ROOT_PATH_BOTH
+  )
+endif()
+
+if(CMAKE_C_COMPILER)
+  if(NOT CMAKE_CXX_COMPILER)
+    string(REGEX REPLACE "clang(|-[0-9]+[\\.0]*)$" "clang++\\1" CMAKE_CXX_COMPILER "${CMAKE_C_COMPILER}")
+    if(NOT EXISTS "${CMAKE_CXX_COMPILER}") # homebrew, clang-6.0 but clang++ has no suffix
+      string(REGEX REPLACE "clang(|-[0-9]+[\\.0]*)$" "clang++" CMAKE_CXX_COMPILER "${CMAKE_C_COMPILER}")
+    endif()
+  endif()
+  if(NOT LD_LLD)
+    string(REGEX REPLACE ".*clang(|-[0-9]+[\\.0]*)$" "lld\\1" LD_LLD "${CMAKE_C_COMPILER}")
+    execute_process(
+      COMMAND ${CMAKE_C_COMPILER} -print-prog-name=${LD_LLD}
+      OUTPUT_VARIABLE LD_LLD_PATH
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(NOT EXISTS ${LD_LLD_PATH}) # llvm on macOS(via brew) has lld but not lld-?
+      set(LD_LLD lld)
+    endif()
+  endif()
+else()
+  set(CMAKE_C_COMPILER clang)
+  set(CMAKE_CXX_COMPILER clang++)
+  set(LD_LLD lld)
+endif()
+
+# llvm-ranlib is for bitcode. but seems works for others. "llvm-ar -s" should be better
+# macOS system ranlib does not work
+execute_process(
+  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-ranlib
+  OUTPUT_VARIABLE CMAKE_RANLIB
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+# llvm-ar for all host platforms. support all kinds of file, including bitcode
+execute_process(
+  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-ar
+  OUTPUT_VARIABLE CMAKE_LLVM_AR
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+execute_process(
+  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-readelf
+  OUTPUT_VARIABLE READELF
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+execute_process(
+  COMMAND ${CMAKE_C_COMPILER} -print-prog-name=llvm-objcopy
+  OUTPUT_VARIABLE CMAKE_LLVM_OBJCOPY
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+get_filename_component(LLVM_DIR ${CMAKE_RANLIB} DIRECTORY)
+
+# Sysroot.
+#message("CMAKE_SYSROOT_COMPILE: ${CMAKE_SYSROOT_COMPILE}, ${CMAKE_CROSSCOMPILING}")
+if(EXISTS "${LINUX_SYSROOT}")
+  set(CMAKE_SYSROOT ${LINUX_SYSROOT})
+# CMake 3.9 tries to use CMAKE_SYSROOT_COMPILE before it gets set from CMAKE_SYSROOT, which leads to using the system's /usr/include. Set this manually.
+# https://github.com/android-ndk/ndk/issues/467
+  set(CMAKE_SYSROOT_COMPILE "${CMAKE_SYSROOT}")
+endif()
+if(CMAKE_CROSSCOMPILING) # default is true
+  set(ENV{PKG_CONFIG_PATH} "${CMAKE_SYSROOT}/usr/share/pkgconfig:${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPPLE}/pkgconfig")
+endif()
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+
+if(USE_LIBCXX)
+  if(CMAKE_CROSSCOMPILING AND USE_TARGET_LIBCXX) # assume libc++ abi is stable, then USE_TARGET_LIBCXX=0 is ok, i.e. build with host libc++, but run with a different target libc++ version
+  # headers in clang builtin include dir(stddef.h etc.). -nobuiltininc makes cross build harder if a header is not found in sysroot(include_next stddef.h in /usr/include/linux/)
+    # -nostdinc++: clang always search libc++(-stdlib=libc++) in host toolchain, may mismatch with target libc++ version, and results in conflict(include_next)
+    if(CMAKE_VERSION VERSION_LESS 3.3)
+      set(LINUX_FLAGS_CXX "${LINUX_FLAGS_CXX} -nostdinc++ -iwithsysroot /usr/include/c++/v1")
+    else()
+      #add_compile_options("$<$<COMPILE_LANGUAGE:CXX>:-stdlib=libc++>")
+      add_compile_options("$<$<COMPILE_LANGUAGE:CXX>:-nostdinc++;-iwithsysroot;/usr/include/c++/v1>")
+    endif()
+    # -stdlib=libc++ is not required if -nostdinc++ is set(otherwise warnings)
+    link_libraries(-stdlib=libc++) #unlike SUNXI_LD_FLAGS, it will append flags to last
+  else()
+    set(LINUX_FLAGS_CXX "${LINUX_FLAGS_CXX} -stdlib=libc++") # for both compiler & linker
+  endif()
+  if(USE_CXXABI)
+    set(LINUX_LINK_FLAGS_CXX "${LINUX_LINK_FLAGS_CXX} -l${USE_CXXABI}") # required if libc++ is built with none abi. otherwise libc++.so is a ld script contains an abi library, e.g. -lc++abi/-lstdc++/-lsupc++
+  endif()
+  #check_library_exists:  compiler must be detected
+  # old libc + old libc++abi: DO NOT use thread_local
+  # new/old libc + new libc++abi: use libc++abi tls/fallback
+  # new libc + old libc++abi: can not ensure libc runtime thread_local support
+  # old libc + stdc++ abi: disable thread_local, stdc++(g++8.0) does not use __cxa_thread_atexit_impl as weak symbol, so can not run on old glibc runtime
+  set(LIBCXX_SO "${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPPLE}/libc++.so.1")
+  if(EXISTS ${LIBCXX_SO})
+    execute_process(
+      COMMAND ${READELF} -needed-libs ${LIBCXX_SO}
+      OUTPUT_VARIABLE LIBCXX_NEEDED
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    string(FIND "${LIBCXX_NEEDED}" libc++abi.so.1 LIBCXX_ABI_LIBCXXABI) # TODO: built with static libc++abi, check exported abi symbols
+    if(LIBCXX_ABI_LIBCXXABI EQUAL -1)
+      #message("libc++ is not built with libc++abi. not safe to use thread_local on old libstdc++ runtime for libc++<7.0")
+      #set(USE_STD_TLS OFF)
+    else()
+      set(LIBCXXABI_SO "${CMAKE_SYSROOT}/usr/lib/${TARGET_TRIPPLE}/libc++abi.so.1") #LIST_DIRECTORIES must be true (false by default for GLOB_RECURSE)
+      if(EXISTS ${LIBCXXABI_SO})
+        execute_process(
+          COMMAND ${READELF} -symbols ${LIBCXXABI_SO}
+          OUTPUT_VARIABLE LIBCXXABI_SYMBOLS
+          OUTPUT_STRIP_TRAILING_WHITESPACE
+        )
+        string(REGEX MATCH "WEAK [A-Z ]* __cxa_thread_atexit_impl" WEAK__cxa_thread_atexit_impl "${LIBCXXABI_SYMBOLS}")
+        string(REGEX MATCH "GLOBAL [A-Z ]* __cxa_thread_atexit_impl" __cxa_thread_atexit_impl "${LIBCXXABI_SYMBOLS}") # UND __cxa_thread_atexit_impl@GLIBC_2.18
+        if(NOT WEAK__cxa_thread_atexit_impl AND NOT __cxa_thread_atexit_impl)
+          message("libc++abi in build environment is too old to support thread_local on old libc runtime")
+          #set(USE_STD_TLS OFF)
+        endif()
+      endif()
+    endif()
+  endif()
+  set(LIBC_SO "${CMAKE_SYSROOT}/lib/${TARGET_TRIPPLE}/libc.so.6")
+  execute_process(
+    COMMAND ${READELF} -symbols ${LIBC_SO}
+    OUTPUT_VARIABLE LIBC_SYMBOLS
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+  )
+  string(FIND "${LIBC_SYMBOLS}" __cxa_thread_atexit_impl HAS__cxa_thread_atexit_impl)
+  if(HAS__cxa_thread_atexit_impl EQUAL -1 AND NOT WEAK__cxa_thread_atexit_impl) # old libc + stdc++/libc++abi<4.0
+    # libc++abi 4.0+ check use __cxa_thread_atexit_impl as weak symbol, and can fallback to libc++ own implementation
+    message(STATUS "libc in build environment is too old to support C++11 thread_local without libc++abi 4.0+")
+    set(USE_STD_TLS OFF)
+  endif()
+  #if(USE_STD_TLS AND NOT HAS__cxa_thread_atexit_impl EQUAL -1) # AND c++abi is none or libc++abi<4.0, then __cxa_thread_atexit generated by clang(for thread_local) can be replaced by __cxa_thread_atexit_impl
+  #  link_libraries(-Wl,-defsym,__cxa_thread_atexit=__cxa_thread_atexit_impl) # libc++ abi is not libc++abi, e.g. stdc++/supc++ abi. clang generated __cxa_thread_atexit is defined in libc++abi 4.0+
+  #endif()
+else() # gcc files can be found by clang
+  if(NOT USE_STDCXX VERSION_LESS 4.8)
+  # Selected GCC installation: always the last (greatest version), no way to change it
+    add_compile_options(-nostdinc++)
+    #file(GLOB_RECURSE CXX_DIRS LIST_DIRECTORIES true "${CMAKE_SYSROOT}/usr/include/*c++") # c++ is dir, so LIST_DIRECTORIES must be true (false by default for GLOB_RECURSE)
+    add_compile_options("-cxx-isystem${CMAKE_SYSROOT}/usr/include/c++/${USE_STDCXX}") # no space after -cxx-isystem
+    add_compile_options("-cxx-isystem${CMAKE_SYSROOT}/usr/include/${TARGET_TRIPPLE}/c++/${USE_STDCXX}") # no space after -cxx-isystem
+  endif()
+endif()
+
+if(CLANG_AS_LINKER)
+  link_libraries(-Wl,--build-id -fuse-ld=${LD_LLD}) # -s: strip
+  if(USE_COMPILER_RT)
+    link_libraries(-rtlib=compiler-rt)
+  endif()
+else()
+  #set(CMAKE_LINER      "${LD_LLD}" CACHE INTERNAL "linker" FORCE)
+  set(LINUX_LD_FLAGS "${LINUX_LD_FLAGS} --build-id --sysroot=${CMAKE_SYSROOT}") # -s: strip
+  macro(set_cc_clang lang)
+    set(CMAKE_${lang}_LINK_EXECUTABLE
+        "<CMAKE_LINKER> -flavor gnu <CMAKE_${lang}_LINK_FLAGS> <LINK_FLAGS> <LINK_LIBRARIES> <OBJECTS> -o <TARGET>")
+    set(CMAKE_${lang}_CREATE_SHARED_LIBRARY
+        "<CMAKE_LINKER> -flavor gnu <CMAKE_${lang}_LINK_FLAGS> <CMAKE_SHARED_LIBRARY_${lang}_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
+    set(CMAKE_${lang}_CREATE_SHARED_MODULE
+        "<CMAKE_LINKER> -flavor gnu <CMAKE_${lang}_LINK_FLAGS> <CMAKE_SHARED_MODULE_${lang}_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
+  endmacro()
+  set_cc_clang(C)
+  set_cc_clang(CXX)
+endif()
+#53472, 5702912
+# Set or retrieve the cached flags. Without these compiler probing may fail!
+
+set(CMAKE_AR         "${CMAKE_LLVM_AR}" CACHE INTERNAL "${CMAKE_SYSTEM_NAME} ar" FORCE)
+set(CMAKE_OBJCOPY    "${CMAKE_LLVM_OBJCOPY}" CACHE INTERNAL "${CMAKE_SYSTEM_NAME} objcopy" FORCE)
+set(CMAKE_C_FLAGS    "${LINUX_FLAGS}" CACHE INTERNAL "${CMAKE_SYSTEM_NAME} c compiler flags" FORCE)
+set(CMAKE_CXX_FLAGS  "${LINUX_FLAGS} ${LINUX_FLAGS_CXX}"  CACHE INTERNAL "${CMAKE_SYSTEM_NAME} c++ compiler/linker flags" FORCE)
+set(CMAKE_ASM_FLAGS  "${LINUX_FLAGS}"  CACHE INTERNAL "${CMAKE_SYSTEM_NAME} asm compiler flags" FORCE)
+set(CMAKE_CXX_LINK_FLAGS "${LINUX_LINK_FLAGS_CXX}" CACHE INTERNAL "additional c++ link flags")
+set(LD_LLD "${LD_LLD}" CACHE INTERNAL "${LD_LLD} as linker" FORCE)
+# CMAKE_C_FLAGS_MINSIZEREL_INIT: will append -Os by cmake, which is not expected, and results in lto link error
+set(CMAKE_C_FLAGS_MINSIZEREL "-Xclang -Oz -DNDEBUG") # -Xclang is required because c/c++ flags is passed to linker and not recognized by linker(-O1/2 is ok, -Os/z is not)
+set(CMAKE_CXX_FLAGS_MINSIZEREL "-Xclang -Oz -DNDEBUG")
+
+set(CMAKE_BUILD_WITH_INSTALL_RPATH ON)
diff --git a/docs/README_CI.md b/docs/README_CI.md
index efb026b..4d7eecc 100644
--- a/docs/README_CI.md
+++ b/docs/README_CI.md
@@ -1,66 +1,66 @@
-# LibGD CI
-
-LibGD uses github actions for CI.
-
-The platforms used are:
-- Ubuntu 20.04LTS, Intel
-    - https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md
-    - GCC (x64)
-    - CLang (x64)
-- Ubuntu 20.04LTS, ARM (graviton2)
-    - AWS Ubuntu Image
-    - GCC (64bit)
-    - CLang (64bit)
-- Windows Server 2019, x64
-    - https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md
-    - Visual Studio Enterprise 2019 (x64, x86 and arm64 cross compiliations)
-    - MingW GCC (x86, x64 and ucrt64)
-- MacOS 11, Intel
-    - https://github.com/actions/virtual-environments/blob/main/images/macos/macos-11-Readme.md
-    - GCC x64
-- MacOS 11, M1 in place but we don't manage to get M1 runners
-
-The CI configurations and script can be found in
-
-```
-.gihub/workflows
-```
-
-## Where are they used
-
-The actions work on:
-- master push
-- any new pull requests
-- GD3 (branch surface/surface)
-
-Please do not merge pull requests can be merged if any of the CI failed.
-
-## ci_ubuntu
-
-This file contains all Linux/Ubuntu configurations. The dependencies are installed using apt. Some libraries may use non official Ubuntu repositories to get the latest versions.
-
-## ci_windows.yml 
-
-It contains all jobs and matrices for VS builds (cross compilations included).
-
-Dependencies are installed using archived VCPKG libraries, from:
-
-https://github.com/libgd/libgd-windows-vcpkg-prebuild
-
-For x64, x86 and arm64.
-
-## ci_windows.yml 
-
-## ci_macos.yml
-
-All configs for MacOS. Dependencies are installed using homebrew (for those not available already in the image).
-
-Important note:
-
-Github actions MacOS images contain Mono. Mono somehow messes up with the various paths and it is not worth figuring out how to work around it. We use a script to simply remove Mono from the system, the script can be found in .github\scripts\removemono.sh
-
-## shellcheck.yml
-
-CI to valid shell scripts syntax, portability or other possible issues. It uses https://www.shellcheck.net/.
-
-If a script is needed with some shell specific features which are raised as error by shellcheck, please use the ignore rules in the top of the script or at the required line(s). For an example, removemono.sh contains such rules.
\ No newline at end of file
+# LibGD CI
+
+LibGD uses github actions for CI.
+
+The platforms used are:
+- Ubuntu 20.04LTS, Intel
+    - https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md
+    - GCC (x64)
+    - CLang (x64)
+- Ubuntu 20.04LTS, ARM (graviton2)
+    - AWS Ubuntu Image
+    - GCC (64bit)
+    - CLang (64bit)
+- Windows Server 2019, x64
+    - https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md
+    - Visual Studio Enterprise 2019 (x64, x86 and arm64 cross compiliations)
+    - MingW GCC (x86, x64 and ucrt64)
+- MacOS 11, Intel
+    - https://github.com/actions/virtual-environments/blob/main/images/macos/macos-11-Readme.md
+    - GCC x64
+- MacOS 11, M1 in place but we don't manage to get M1 runners
+
+The CI configurations and script can be found in
+
+```
+.gihub/workflows
+```
+
+## Where are they used
+
+The actions work on:
+- master push
+- any new pull requests
+- GD3 (branch surface/surface)
+
+Please do not merge pull requests can be merged if any of the CI failed.
+
+## ci_ubuntu
+
+This file contains all Linux/Ubuntu configurations. The dependencies are installed using apt. Some libraries may use non official Ubuntu repositories to get the latest versions.
+
+## ci_windows.yml
+
+It contains all jobs and matrices for VS builds (cross compilations included).
+
+Dependencies are installed using archived VCPKG libraries, from:
+
+https://github.com/libgd/libgd-windows-vcpkg-prebuild
+
+For x64, x86 and arm64.
+
+## ci_windows.yml
+
+## ci_macos.yml
+
+All configs for MacOS. Dependencies are installed using homebrew (for those not available already in the image).
+
+Important note:
+
+Github actions MacOS images contain Mono. Mono somehow messes up with the various paths and it is not worth figuring out how to work around it. We use a script to simply remove Mono from the system, the script can be found in .github\scripts\removemono.sh
+
+## shellcheck.yml
+
+CI to valid shell scripts syntax, portability or other possible issues. It uses https://www.shellcheck.net/.
+
+If a script is needed with some shell specific features which are raised as error by shellcheck, please use the ignore rules in the top of the script or at the required line(s). For an example, removemono.sh contains such rules.