fuzz: if the caller of our makefile sets CC and CXX, trust them...
fuzz: if the caller of our makefile sets CC and CXX, trust them
This should fix the broken fuzzing build, because we've been
explicitly using clang++ but are now being given a CXX=afl++, which
does extra stuff.
Differential Revision:
https://phab.mercurial-scm.org/D10066