- put a 'standards conforming' memcmp into memcmp.c
- make bcmp be a second label on the same code
- make bcmp.c be just #include "memcmp.c"
This means that libsa.o might contain both a memcmp.o and a bcmp.o, but
both contain the same code (defining both symbols) so it doesn't matter
which ld uses.
Saves worrying about which of bcmp.c and memcmp.c the architecture specific
Makefile requests.
So make bcmp.c define bcmp and memcmp.
This should (?) fix the atari build.
(I've now no idea why the previous change defined memcpy for the alpha build.)