Added a revision number for easy compile-time tests.

build-scripts/updaterev.sh

@@ -9,7 +9,9 @@ header=$outdir/include/SDL_revision.h
 
 rev=`sh showrev.sh 2>/dev/null`
 if [ "$rev" != "" -a "$rev" != "hg-0:baadf00d" ]; then
+    revnum=`echo $rev | sed 's,hg-\([0-9]*\).*,\1,'`
     echo "#define SDL_REVISION \"$rev\"" >$header.new
+    echo "#define SDL_REVISION_NUMBER $revnum" >>$header.new
     if diff $header $header.new >/dev/null 2>&1; then
         rm $header.new
     else