Add libv4l2 as requirement for the v4l2 plugin.

In order to convert formats not natively supported by obs the
v4l2 userspace library is required. This patch adds a cmake
script to find the library.

plugins/linux-v4l2/CMakeLists.txt

@@ -1,5 +1,13 @@
 include_directories(SYSTEM "${CMAKE_SOURCE_DIR}/libobs")
 
+find_package(Libv4l2)
+if(NOT LIBV4L2_FOUND)
+	message(STATUS "libv4l2 not found, disabling v4l2 plugin")
+	return()
+endif()
+
+include_directories(SYSTEM "${CMAKE_SOURCE_DIR}/libobs")
+
 set(linux-v4l2_SOURCES
 	linux-v4l2.c
 	v4l2-input.c
@@ -10,6 +18,7 @@ add_library(linux-v4l2 MODULE
 )
 target_link_libraries(linux-v4l2
 	libobs
+	${LIBV4L2_LIBRARIES}
 )
 
 install_obs_plugin(linux-v4l2)