Oh, very neat - "make MAKECONF=/usr/pkg/etc/gcc-2.95.2.mk" in userland 
directories seems to DTRT.   For example, as far as I can tell, 
making this way in /usr/src/usr.bin/vi results in a working vi binary.
Likewise, at least the right binaries seem to be invoked when
compiling up a kernel, although I haven't tried booting a kernel
built this way (yet).

There may be code generation problems or somesuch though. :-( 
For example, cd /usr/src/regress; make cleandir; make "MAKECONF...";
make "MAKECONF..." regress results in:

regress ===> lib/libc/ieeefp/round
./round
assertion "FLT_ROUNDS == 2" failed: file "/usr/src/regress/lib/libc/ieeefp/round/round.c", line 29
*** Signal 6

Stop.

This may be options pollution that is my fault.

I will play with this when I am conscious again.

	Sean.