build: build squirrel and its dependencies from source (#24318)

* build: build squirrel and its dependencies from source

* chore: do not use fork for squirrel.mac

* build: do not ship headers with dependency frameworks

* Update BUILD.gn

* chore: s/striped/stripped

* chore: update as per feedback

* chore: use ARC and fix build errors

* chore: fix ARC Squirrel self retainer

build/strip_framework.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+import os
+import subprocess
+import sys
+
+source = sys.argv[1]
+dest = sys.argv[2]
+
+# Ensure any existing framework is removed
+subprocess.check_output(["rm", "-rf", dest])
+
+subprocess.check_output(["cp", "-a", source, dest])
+
+# Strip headers, we do not need to ship them
+subprocess.check_output(["rm", "-r", os.path.join(dest, 'Headers')])
+subprocess.check_output(["rm", "-r", os.path.join(dest, 'Versions', 'Current', 'Headers')])