build: add new version mechanism based on VERSION file and a version.sh script

If this is a git checkout, and git is available, then git describe is
used. Otherwise, the new checked in VERSION file is taken for the version.

This mechanism uses a version.sh script inspired by
http://git.musl-libc.org/cgit/musl/tree/tools/version.sh

Signed-off-by: Michael Adam <obnox@samba.org>

Makefile.am

@@ -4,7 +4,8 @@ SUBDIRS = \
 	etc \
 	docs \
 	m4macros \
-	tests
+	tests \
+	scripts
 
 # tools want this on a single line
 ACLOCAL_AMFLAGS = -I m4macros
@@ -20,7 +21,8 @@ dist_doc_DATA = \
 EXTRA_DIST = \
 	autogen.sh \
 	tinyproxy-indent.sh \
-	TODO
+	TODO \
+	VERSION
 
 test: all
 	./tests/scripts/run_tests.sh

VERSION

@@ -0,0 +1 @@
+1.10.0

configure.ac

@@ -3,15 +3,7 @@
 
 AC_PREREQ(2.54)
 
-m4_define([tinyproxy_major_version], [1])
-m4_define([tinyproxy_minor_version], [10])
-m4_define([tinyproxy_micro_version], [0])
-m4_define([tinyproxy_real_version],
-          [tinyproxy_major_version.tinyproxy_minor_version.tinyproxy_micro_version])
-m4_define([tinyproxy_version], [tinyproxy_real_version])
-
-# For overriding the version string. Comment out if not needed.
-# m4_define([tinyproxy_version], [1.10.0])
+m4_define([tinyproxy_version], esyscmd(sh scripts/version.sh | tr -d '\n'))
 
 AC_INIT([Tinyproxy], [tinyproxy_version],
 	[https://tinyproxy.github.io/],
@@ -227,6 +219,7 @@ docs/man8/tinyproxy.txt
 m4macros/Makefile
 tests/Makefile
 tests/scripts/Makefile
+scripts/Makefile
 ])
 
 AC_OUTPUT

scripts/Makefile.am

@@ -0,0 +1,2 @@
+EXTRA_DIST = \
+	     version.sh

scripts/version.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+SCRIPT_DIR="$(cd "$(dirname "${0}")" && pwd)"
+GIT_DIR="${SCRIPT_DIR}/../.git"
+
+if test -d "${GIT_DIR}" ; then
+	if type git >/dev/null 2>&1 ; then
+		git describe --match '[0-9]*.[0-9]*.[0-9]*' 2>/dev/null \
+			| sed -e 's/-/-git-/'
+	else
+		sed 's/$/-git/' < VERSION
+	fi
+else
+	cat VERSION
+fi