The names of m-d variants are now added (manually) to MDSRCS instead
of to SRCS, and the names of all machine-independent (m-i) variants
that can reasonably be replaced by an m-d variant are now added
(manually) to MISRCS instead of to SRCS, so that a simple substitution
can be used to discard the unused m-i variants. MISRCS is potentially
all m-i sources, but the substitution is too simple to be fast, so
MISRCS should be kept reasonably small.
libc/Makefile.inc:
Do the substitution.
libc/i386/string/Makefile.inc:
Add to MDSRCS instead of to SRCS. Add the names of all sources in this
directory, but no others.
libc/string/Makefile.inc
Add to MISRCS instead of to SRCS. Add the names of all sources in this
directory. Don't use (broken) explicit rules for special cases.