ocaml: don't use the spack compiler (#38251)

Co-authored-by: jmcarcell <jmcarcell@users.noreply.github.com>

var/spack/repos/builtin/packages/ocaml/package.py

@@ -70,7 +70,7 @@ def install(self, spec, prefix):
                     string=True,
                 )
 
-        configure(*(base_args))
+        configure(*(base_args), f"CC={self.compiler.cc}")
 
         make("world.opt")
         make("install", "PREFIX={0}".format(prefix))