Remove unused code that costs a good bit of performance.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36492 b3059339-0415-0410-9bf9-f77b7e298cf2
Remove unused per-channel enable.

It makes it hard to vectorize or otherwise optimize the code.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36493 b3059339-0415-0410-9bf9-f77b7e298cf2
Fix configure for cases when libm is not available.

This seems to be the case for e.g. Haiku.
Admittedly supporting such different-for-no-good-reason
setups is a bit questionable, but it's not much effort
in this case.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36494 b3059339-0415-0410-9bf9-f77b7e298cf2
Fall back to uname -p if uname -m does not give anything useful.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@36495 b3059339-0415-0410-9bf9-f77b7e298cf2