Setting GSSAPILDFLAGS for USES=gssapi causes -L/usr/lib to be added to LDFLAGS.
This breaks compilation of some ports, like www/squid on GCC architectures when new GCC from ports needs to be used.
The new GCC tries to link to libstdc++ and fails. Not setting it explicitely causes /usr/local/lib/gcc8/libstdc++.so to be taken instead and /usr/lib is searched for libraries anyway, just with lower priority.
Tested on powerpc64 and amd64 on www/squid.
PR: 237275