[mythtv] CVS + !MMX doesn't compile (and other ./configure issues)

[Chris Petersen]

> Ok, I've added an --enable-mmx parameter. I don't think it's a good
> idea to compile for i386, I think it would be better to optimize for
> the pentium-mmx, and let those with pre-mmx processors compile their
> own. I had a dual pentium-pro machine once, top of the line, it ran
> at a 200Mhz. There is no way it could run a frontend, and as far as
> a backend goes the slots were probably PCI v1.0... Also even if you
> make a pentium-mmx version, you should at least make a pentium2
> version, the cmov instruction alone results in a 10% speedup for
> ffmpeg.

Yes, I'm aware that it's not a great idea, but redhat has it "on good 
authority" that i386 tuned for ppro or p4 is actually faster in most 
cases than i586 turned for ppro or p4.  can't move to i686 because of 
missing registers (or something like that, I'm not a cpu guy) in the via 
procs (which is apparently the only difference between 586 and 686 to 
gcc).

I do plan to make a couple of different versions of the rpm (even though 
the fedora guys don't really want to deal with it), but want to make 
sure that the handful that I make will work for as many people as 
possible (and then I'll try to make it easy for people to build their 
own from the src.rpm and use the new auto-detection stuff for best 
optimization)  Unfortunately, right now, I can't seem to get things to 
accept the make parameters passed in by rpmbuild, so I have to recreate 
all of the arch stuff by hand.  (Axel's rpm's manually add them to 
QMAKE_CXXFLAGS_RELEASE and QMAKE_CFLAGS_RELEASE, after doing a "-= 
pentiumpro" but that doesn't seem to do anything for me, even if I 
hard-code pentiumpro into the configure phase)

Incidentally, is pentium2 better/worse than pentiumpro?

And is there any particular reason why this sort of 
detection/optimization isn't done in runtime like it is with programs 
like mplayer?

> It looks like the libmythmpeg2 library that was added a few
> weeks ago did not have "#ifdef MMX" protection around a couple
> MMX parts. It should be ok now.

Thanks.

-Chris