audio/libmp3splt: Fix configure script test for modern binutils
The id3tag library will fail to be detected on systems using ld from
recent binutils. This is because libid3tag is linked without zlib also
being linked directly, and be default it doesn't search libraries linked
to linked libraries. The configure script is patched with "-lz" to fix.
Also remove redundant MAKE_JOBS_SAFE while we are here.
Approved by: bapt (mentor), maintainer