Don't generate _G_config.h, use fixed version.

Don't generate _G_config.h, use fixed version.
I knew better... too dependant on the environment we generate in, but...

This fixes the
/usr/lib/libstdc++.so: undefined reference to `filebuf virtual table'
/usr/lib/libstdc++.so: undefined reference to `stdiobuf virtual table'
errors seen after the initial bootstrap from gcc 2.7.2 to EGCS.

Agreed with by:	bde & jdp