VERSION obtained from source instead of the previous git tag.

Drawback: The version string is no longer a valid git identifier.
          For this reason the 'g' short hash prefix has been removed.

Exception: When building directly from a tag this behaves exactly like the previous behavior.
           This allows formatting release versions with precision     i.e. v0.9.2
           This also allows arbitrary topicbranch names               i.e. v0.9.1-glibc-compat

share/genbuild.sh

@@ -14,13 +14,21 @@ else
 fi
 
 DESC=""
+SUFFIX=""
 LAST_COMMIT_DATE=""
 if [ -e "$(which git)" -a -d ".git" ]; then
     # clean 'dirty' status of touched files that haven't been modified
     git diff >/dev/null 2>/dev/null 
 
-    # get a string like "v0.6.0-66-g59887e8-dirty"
-    DESC="$(git describe --dirty 2>/dev/null)"
+    # if latest commit is tagged and not dirty, then override using the tag name
+    RAWDESC=$(git describe --abbrev=0 2>/dev/null)
+    if [ "$(git rev-parse HEAD)" = "$(git rev-list -1 $RAWDESC)" ]; then
+        git diff-index --quiet HEAD -- && DESC=$RAWDESC
+    fi
+
+    # otherwise generate suffix from git, i.e. string like "59887e8-dirty"
+    SUFFIX=$(git rev-parse --short HEAD)
+    git diff-index --quiet HEAD -- || SUFFIX="$SUFFIX-dirty"
 
     # get a string like "2012-04-10 16:27:19 +0200"
     LAST_COMMIT_DATE="$(git log -n 1 --format="%ci")"
@@ -28,6 +36,8 @@ fi
 
 if [ -n "$DESC" ]; then
     NEWINFO="#define BUILD_DESC \"$DESC\""
+elif [ -n "$SUFFIX" ]; then
+    NEWINFO="#define BUILD_SUFFIX $SUFFIX"
 else
     NEWINFO="// No build information available"
 fi