[Mjpeg-users] Manually setting host CPU for mjpegtools

[LRN <lr...@gm...>]

I'm building mjpegtools with mingw32 gcc 4.5.2 and msys.
When i configure it as-is, it detects my cpu as core2 (which is correct) 
and compiles with -mcpu=core2 -mtune=core2
It is commendable. However, i would like to compile a version that will 
run on any more-or-less contemporary device, which means either 
-mtune=i686 or -mtune=generic
I've tried building with --host=i686-pc-mingw32 (that is how mingw32 
often identifies itself), but hit the problem with sigjmp_buf being 
undefined (googling for it didn't do any good), and generic-pc-mingw32 
fails outright, since `generic' is not a correct cpu.
So, in the end i want two things:
1) -mtune=generic
2) undefined HAVE_X86_CPU, which will prevent sigjmp_buf-related code 
from being compiled