Greg Jandl to SDL I did some digging, and I think I've found a better solution. By including some additional .m4 macros in the acinclude directory (http://www.gnu.org/software/autoconf-archive/ax_check_compiler_flags.html, http://www.gnu.org/software/autoconf-archive/ax_gcc_archflag.html and http://www.gnu.org/software/autoconf-archive/ax_gcc_x86_cpuid.html) then using the patch below (same as previous patch + one line change to configure.in), SDL will build correctly out of the box. The arch can then be overridden by --with-gcc-arch=<arch> (most will probably want to build with i686 there for general distribution) or --without-gcc-arch, to disable setting the arch all together. On my Atom netbook, I get -march=PentiumPro by default, which works great, as does --with-gcc-arch=i686.

#!/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 [ "$rev" != "" -a "$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