Checking for kernel support of mmx ... failed
It seems that your kernel does not correctly support mmx.
To use mmx extensions in MPlayer, you have to upgrade/recompile your kernel!
Checking for kernel support of mmxext ... failed
It seems that your kernel does not correctly support mmxext.
To use mmxext extensions in MPlayer, you have to upgrade/recompile your kernel!
Checking for kernel support of sse ... failed
It seems that your kernel does not correctly support sse.
To use sse extensions in MPlayer, you have to upgrade/recompile your kernel!
Checking for kernel support of sse2 ... failed
It seems that your kernel does not correctly support sse2.
To use sse2 extensions in MPlayer, you have to upgrade/recompile your kernel!
Checking for kernel support of ssse3 ... failed
It seems that your kernel does not correctly support ssse3.
To use ssse3 extensions in MPlayer, you have to upgrade/recompile your kernel!
Checking for kernel support of cmov ... failed
It seems that your kernel does not correctly support cmov.
To use cmov extensions in MPlayer, you have to upgrade/recompile your kernel!
Checking for mtrr support ... yes
Checking for GCC & CPU optimization abilities ... ./configure: line 1961: test: !=: unary operator expected
CPU optimization disabled. CPU not recognized or your compiler is too old.
error
Checking for byte order ... failed to autodetect byte order, defaulting to little-endian
Checking for extern symbol prefix ...
Error: Symbol mangling check failed.

Check "config.log" if you do not understand why it failed.

Is there a question in there somewhere???

And if you'd like help, you need to ask a clear question, and provide details. Things like version/distro of Linux, what you did/are doing to GET the error, and what you've tried. Did you bother to check the config.log file, as the program told you? Do you HAVE an MMX capable system? Did you read the mplayer docs, to see how to enable/disable that option?