[PATCH] configure: Check for the -Wno-force-align-arg-pointer compiler switch.

[Charles Davis]

Charles Davis wrote:
> I added this to clang yesterday. Now clang will warn every time it
> encounters the force_align_arg_pointer attribute applied to a function
> pointer. This isn't a problem on Linux, but on Mac OS X those warnings
> are going to clutter the output, since we use it so liberally.
All right, since you're not convinced this is a good idea, let me, well,
convince you.

The conversation I had on the cfe-commits mailing list:
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100208/027361.html
(my original commit)
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100208/027392.html
(someone suggesting the warning)
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100208/027395.html
(someone else seconding it)
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100208/027396.html
(me saying no)
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100208/027397.html
(a third person suggesting the switch)
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100208/027420.html
(me caving)

An incomplete list of projects that use force_align_arg_pointer:
- liboil
- ffmpeg
- x264
- Gallium3D
- KDE

Just do a Google search for 'force_align_arg_pointer' and you'll see a
whole bunch of pages about this!

Now are you convinced this is a good idea?

Chip