Just build, do not bootstrap, this stable, default version of GCC
in our ports tree. This speeds up a full port/package test cycle
by 31% on a 4-core system; a simple build/install will benefit even
(This may impact compile time by this compiler a bit, depending on
how well the system compiler optimizes this codebase. And we only
should do this for stable, established versions of GCC.)
Remove ABI version numbers for all library dependencies.