misc/scripts: remove Darwin cpp wrapper

This wrapper around Apple llvm-gcc has been obsolete and unused for a
few years now. Remove to avoid confusion.

Signed-off-by: Gerwin Klein <gerwin.klein@proofcraft.systems>

misc/scripts/cpp

@@ -1,13 +0,0 @@
-#!/bin/bash
-#
-# Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
-#
-# SPDX-License-Identifier: BSD-2-Clause
-#
-
-#
-# Wrapper for clang C preprocessor on MacOS
-#
-export L4CPP="-DTARGET=ARM -DTARGET_ARM -DPLATFORM=Sabre -DPLATFORM_Sabre"
-
-llvm-gcc -Wno-invalid-pp-token -E -x c $@