This causes clang to give fewer warnings of implicit declarations of
functions.
In mach/pdp/cv/cv.c, rename wr_int2() to cv_int2() because it
conflicts with wr_int2() in <object.h>.
In util/ack, rename F_OK to F_TRANSFORM because it conflicts with F_OK
for access() in <unistd.h>.
Edit build.lua for programs losing their private assert.h, so they
depend on a list of .h files excluding assert.h.
Remove modules/src/assert; it would be a dependency of cpp.ansi but we
didn't build it, so cpp.ansi uses the libc assert.
I hope that libc <assert.h> can better report failed assertions. Some
old "assert.h" files didn't report the expression. Some reported a
literal "x", because traditional C expanded the macro parameter x in
"x", but ANSI C89 doesn't expand macro parameters in string literals.
