mpg123: unbreak static linking with alsa/portaudio

Fixes:
http://autobuild.buildroot.org/results/b2b/b2bc143fbd0b34e75a44af41ab6899dd9fa3c21a/
http://autobuild.buildroot.org/results/60d/60d56b0a75d209f2cfeff0727c2f900abc89d263/
http://autobuild.buildroot.org/results/6a8/6a8729ce69055821fdf0b91adcea2ea201d40189/



And many more.

A recent upstream build system change caused LIBS to be ignored at build
time (but still used a configure time), causing our static linking
workarounds to no longer work.

Fix it by adding a patch to cause it to no longer ignore LIBS.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>