[rfa/rfc] Build libcommon.a for gdb and gdbserver

[Joel Brobecker]

> I think it would be a good idea to require GNU make, but I think that is
> something that needs general agreement.

Since GCC already requires GNU Make, I don't think that it would
be a problem for us to require GNU Make as well.  IIRC, the reason
for not requiring GNU Make was for FreeBSD where it's not installed
by default? It doesn't seem like a strong argument to limit ourselves,
especially considering the fact that they should already know how to
handle this dependency because of GCC.

-- 
Joel