Adjust to changed compilation environment (Makefiles setup) in 5.1-CURRENT.
Link with liblgcc_r when creating linuxthreads versions of shared
libraries.
Build linuxthreads version of libstdc++ and libsupc++ under 5.0-CURRENT.
Don't misuse DESTDIR when building linuxthreads version of libgcc.
Fix varargs warning under 5.0-CURRENT.
Don't try to register profiled libraries when NOPROFILE has been specified.
Don't try to register shared libraries when NOPIC has been specified.
Bump port revision.
PR: 38876
Rather than copying the entirety of src/gnu/lib/libgcc/Makefile, .include it
and override variables as necessary. This vastly shortens this file, makes
tracking toolchain changes more automatic, and makes the linuxthreads port
build on both -stable and -current.