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
#
# Print the current source revision, if available

# FIXME: this prints the tip, which isn't useful if you're on a different
#  branch, or just not sync'd to the tip.
hg tip --template 'hg-{rev}:{node|short}' || (echo "hg-0:baadf00d"; exit 1)