Added a better way to include build rules in the Makefile
Cleaned up dependencies on generating SDL_revision.h
Fixed 'make install' if you are not building from a Mercurial repository
#!/bin/sh
#
# Generate a header file with the current source revision
outdir=`pwd`
cd `dirname $0`
srcdir=..
header=$outdir/include/SDL_revision.h
rev=`sh showrev.sh 2>/dev/null`
if [ "$rev" != "" -a "$rev" != "hg-0:baadf00d" ]; then
echo "#define SDL_REVISION \"$rev\"" >$header.new
if diff $header $header.new >/dev/null 2>&1; then
rm $header.new
else
mv $header.new $header
fi
fi