Log Message:
devel/gps: Remove restriction on NetBSD[56]*

If lang/gcc-aux builds on NetBSD, it will be able to build GPS.
The system linker that lang/gcc-aux used has been replaced with the new
gold linker from devel/binutils (the ld.bfd linker is buggy with regards
to PIC files, the same bug was seen on OpenBSD 5.5).