Generate git version

#!/bin/sh

# Input: version.h.in that includes $VERSION
# Output: version.h

version_file='path/to/version.h'

# Useful for e.g. Jenkins builds. Pass "b$BUILD_INFO" as an argument...
while [ $# != 0 ] ; do
  ver="$ver-$1"
  shift
done

ver=$(git describe --tags)
stash_hash=$(git stash create)
if [ -n "$stash_hash" ]; then
  ver=$(echo "$ver" | sed "s/-g[^-]*$/-s${stash_hash:0:7}/")
fi

echo Using version: $ver

sed "s/\$VERSION/$ver/g" "$version_file.in" > "$version_file.tmp"
if [ ! -f "$version_file" ] || ! diff -q "$version_file.tmp" "$version_file" &> /dev/null; then
  mv "$version_file.tmp" "$version_file"
else
  rm -f "$version_file.tmp"
fi