Of COURSE that trick wouldn't work on all renderers. Fall back to something for now, hopefully figure out a better way to do this later. If we have to, we can use vertical line and horizontal line textures for vertical and horizontal lines, and then create custom textures for diagonal lines and software render those. It's terrible, but at least it would be pixel perfect.

#!/bin/sh
#
# Generate a header file with the current source revision

cd `dirname $0`
srcdir=..
header=$srcdir/include/SDL_revision.h

rev=`sh showrev.sh`
if [ "$rev" != "" ]; 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