git_version_gen.sh

#!/bin/sh

DIR="."

if [ "$#" -gt "0" ]; then
	DIR=$1
fi

GVF=version
DEF_VER=UNKNOWN

LF='
'

cd $DIR

if test -d .git -o -f .git &&
	VN=$(git describe --match "[0-9]*\.[0-9]*" HEAD 2>/dev/null) &&
	case "$VN" in
	*$LF*) (exit 1) ;;
	[0-9]*)
		git update-index -q --refresh
		test -z "$(git diff-index --name-only HEAD --)" ||
		VN="$VN-dirty" ;;
	esac
then
	VN="$VN"
else
	#Git failed to find version number. Falling back to Debian changelog.
	DEBIAN_VERSION=`head debian/changelog  -n 1 | cut -d'(' -f2 |cut -d')' -f1`
	VN="${DEBIAN_VERSION}"
fi
if test -r $GVF
then
	VC=$(cat $GVF)
else
	VC=unset
fi
test "$VN" = "$VC" || {
	echo "$VN" > $GVF
    echo "constexpr auto VERSION = \"$VN\";" > src/version.h
}