Add macros to get the semantic version of the current release

m4/semver.m4

@@ -0,0 +1,6 @@
+AC_SUBST(SOURCE_REVISION)
+
+AC_MSG_CHECKING([for revision])
+SOURCE_REVISION=`$ac_pwd/common/semver.sh`
+AC_MSG_RESULT([$SOURCE_REVISION])
+

semver.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+SOURCE_REVISION=""
+if test -f REVISION; then
+  SOURCE_REVISION=`test -f REVISION && head -n1 REVISION`
+elif test "${PWD##*/}" != "OpenModelica" && test -f ../REVISION; then
+  SOURCE_REVISION="OpenModelica `test -f ../REVISION && head -n1 ../REVISION`"
+elif test -z "$SOURCE_REVISION" && test -e .git; then
+  DESCRIBE_SHORT=`git describe --match "v[0-9]*.[0-9]*.[0-9]*" --always`
+  DESCRIBE_LONG=`git describe --match "v[0-9]*.[0-9]*.[0-9]*" --always --long`
+  if test "$DESCRIBE_SHORT" != "$DESCRIBE_LONG"; then
+    SOURCE_VERSION="$DESCRIBE_SHORT"
+  else
+    HASH=`echo $DESCRIBE_SHORT | rev | cut -d- -f1 | rev`
+    COMMIT_SINCE_LAST=`echo $DESCRIBE_SHORT | rev | cut -d- -f2 | rev`
+    PRERELEASE=`echo $DESCRIBE_SHORT | rev | cut -d- -f3- | rev | cut -d- -f2-`
+    RELEASE_MAJOR=`echo $DESCRIBE_LONG | cut -d. -f1`
+    RELEASE_MINOR=`echo $DESCRIBE_LONG | cut -d. -f2`
+    RELEASE_PATCH=`echo $DESCRIBE_LONG | cut -d. -f3 | cut -d- -f1`
+    if test -z "$PRERELEASE"; then
+      # Invent a pre-release tag
+      PRERELEASE="dev"
+      COMMIT_SINCE_LAST=$(($COMMIT_SINCE_LAST-1))
+      RELEASE_PATCH=$(($COMMIT_SINCE_LAST+1))
+    fi
+    SOURCE_REVISION="$RELEASE_MAJOR.$RELEASE_MINOR.$RELEASE_PATCH-$PRERELEASE.$COMMIT_SINCE_LAST+$HASH"
+  fi
+fi
+test -z "$SOURCE_REVISION" && SOURCE_REVISION="????"
+
+echo "$SOURCE_REVISION"