* gcc_syslibs contains the shared libraries that are being built
as part of gcc, i.e. libgcc_s.so, libsupc++.so and libstdc++.so
* gcc_syslibs_devel contains the static versions of the respective
libraries plus additionally kernel versions of libgcc.a and
libsupc++.a (which do not provide support for pthreads or TLS
and thus do not have any external dependencies). Additionally,
this build feature contains the c++ and gcc headers from the
non-legacy compiler.