Configure: Fix failure of FSEvents to configure with --disable-binary

FSEvents uses AC_CHECK_DECLS in its configure script.  AC_CHECK_DECLS
has an internal test where it tries to figure out what flag to pass
to the compiler to make compilation of a certain piece of code _fail_.
But nobinary_dummy "succeeds" at compiling anything, which makes it
impossible for this configure test to succeed.  Work around the issue
by pre-seeding the cache with the desired outcome for the internal test.

Also, fix the incorrect test guarding the assignment of CC to
$BINDIR/nobinary_dummy.

src/aclocal.m4

@@ -271,11 +271,12 @@ define([MY_AC_PROG_CC],
   AC_PROG_CC
   undefine([ac_cv_prog_CC])
   AC_PROG_CPP
-  if test "x$enable_binary" = "no"; then
+  if test "x$enable_binary" = x"no"; then
     # Do the check above even when --disable-binary is used, since we
     # need a real $CPP, and AC_PROG_CPP wants AC_PROG_CC to be called
     # earlier.
     CC="$BINDIR/nobinary_dummy cc"
+    ac_cv_c_undeclared_builtin_options='none needed'
   fi
 ])