The are no event handlers for the middle mouse button, right mouse buttons, and
mouse wheel in the latest HG revision 4636. It has been like this for 3 months.
I made a patch for this, though I'm not sure if the Xbutton or mouse wheel code
is "correct" by your standards.

in SDL 1.3 (revision 5508 from SVN), the method used to calculate the
bits per pixel from a “int format” differ between “SDL_ListModes” (which
always uses the “SDL_BITSPERPIXEL” macro) and “SDL_PixelFormatEnumTo-
Masks” (which uses either “SDL_BITSPERPIXEL” or “SDL_BYTESPERPIXEL * 8”,
depending on the value of “SDL_BYTESPERPIXEL”).

Because the values are later compared in “SDL_ListModes” this may lead
to some valid video modes not being returned. In my case the only mode
returned by “SDL_GetNumDisplayModes” was dismissed and NULL was
returned. (This led to the calling application sticking its head in the
sand.)

The attached patch copies the method used within “SDL_PixelFormatEnumTo-
Masks” to “SDL_ListModes”. This solved the problem for me though I don't
fully understand the method used by “SDL_PixelFormatEnumToMasks”.

I *think* the patch below works correctly: sdl-config gets the -march
flag and SDL builds fine. Perhaps there's a better way to get the
-march flag into both CFLAGS and SDL_FLAGS w/o dragging along more
cruft, but adding it to BASE_CFLAGS seemed the best bet to my eyes.

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.

Fixed building SDL test programs

That's actually okay, since gcc has the builtin atomic intrinsics. :)