Add a snapshot of flutter/engine/src/build to our sdk

build/mac/verify_no_objc.sh

Index: build/mac/verify_no_objc.sh
diff --git a/build/mac/verify_no_objc.sh b/build/mac/verify_no_objc.sh
new file mode 100755
index 0000000000000000000000000000000000000000..e18a5eafb0054259a79caa53132cbbd5c801fc1f
--- /dev/null
+++ b/build/mac/verify_no_objc.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This script makes sure that no __OBJC,__image_info section appears in the
+# executable file built by the Xcode target that runs the script. If such a
+# section appears, the script prints an error message and exits nonzero.
+#
+# Why is this important?
+#
+# On 10.5, there's a bug in CFBundlePreflightExecutable that causes it to
+# crash when operating in an executable that has not loaded at its default
+# address (that is, when it's a position-independent executable with the
+# MH_PIE bit set in its mach_header) and the executable has an
+# __OBJC,__image_info section. See http://crbug.com/88697.
+#
+# Chrome's main executables don't use any Objective-C at all, and don't need
+# to carry this section around. Not linking them as Objective-C when they
+# don't need it anyway saves about 4kB in the linked executable, although most
+# of that 4kB is just filled with zeroes.
+#
+# This script makes sure that nobody goofs and accidentally introduces these
+# sections into the main executables.
+
+set -eu
+
+executable="${BUILT_PRODUCTS_DIR}/${EXECUTABLE_PATH}"
+
+if xcrun otool -arch i386 -o "${executable}" | grep -q '^Contents.*section$'; \
+then
+  echo "${0}: ${executable} has an __OBJC,__image_info section" 2>&1
+  exit 1
+fi
+
+if [[ ${PIPESTATUS[0]} -ne 0 ]]; then
+  echo "${0}: otool failed" 2>&1
+  exit 1
+fi
+
+exit 0