We can only wrap mmap if it exists.

* mf-hooks1.c (__mf_0fn_mmap, mmap, __mf_0fn_munmap, munmap): Protect
with HAVE_MMAP ifdef.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@104810 138bc75d-0d04-0410-961f-82ee72b054a4