FAAC doesn't compile on GNU/Linux

Due to a known conflict between FAAC and GNU libc (http://sourceforge.net/p/faac/bugs/162/, http://stackoverflow.com/questions/4320226/installing-faac-on-linux-getting-errors), faac 1.28 doesn't compile on glibc-2.10 and later versions.

As many GNU/Linux distros do, the redundant declaration `strcasestr` in `common/mp4v2/mpeg4ip.h` needs to be removed to resolve its conflict with glibc. (Here's a [patch](http://www.linuxfromscratch.org/patches/blfs/svn/faac-1.28-glibc_fixes-1.patch) from LFS)