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

build/mac/copy_asan_runtime_dylib.sh

Index: build/mac/copy_asan_runtime_dylib.sh
diff --git a/build/mac/copy_asan_runtime_dylib.sh b/build/mac/copy_asan_runtime_dylib.sh
new file mode 100755
index 0000000000000000000000000000000000000000..f221c4a66dd83bbccaee2d11b0ee35bfb130b47d
--- /dev/null
+++ b/build/mac/copy_asan_runtime_dylib.sh
@@ -0,0 +1,76 @@
+#!/bin/bash
+
+# Copyright (c) 2013 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.
+
+# For app bundles built with ASan, copies the runtime lib
+# (libclang_rt.asan_osx_dynamic.dylib), on which their executables depend, from
+# the compiler installation path into the bundle and fixes the dylib's install
+# name in the binary to be relative to @executable_path.
+
+set -e
+
+BINARY="${BUILT_PRODUCTS_DIR}/${EXECUTABLE_PATH}"
+
+if [[ ! -f "$BINARY" ]]; then
+  # This is neither an .app bundle nor a standalone executable.
+  # Most certainly the script has been called for a data bundle.
+  exit 0
+fi
+
+BINARY_DIR="$(dirname "${BINARY}")"
+
+# Find the link to the ASan runtime encoded in the binary.
+BUILTIN_DYLIB_PATH=$(otool -L "${BINARY}" | \
+    sed -Ene 's/^[[:blank:]]+(.*libclang_rt\.asan_.*_dynamic\.dylib).*$/\1/p')
+
+if [[ "${BUILTIN_DYLIB_PATH}" == *asan_iossim_dynamic* ]]; then
+  ASAN_DYLIB_NAME=libclang_rt.asan_iossim_dynamic.dylib
+elif [[ "${BUILTIN_DYLIB_PATH}" == *asan_osx_dynamic* ]]; then
+  ASAN_DYLIB_NAME=libclang_rt.asan_osx_dynamic.dylib
+fi
+
+if [[ -z "${BUILTIN_DYLIB_PATH}" ]]; then
+  echo "${BINARY} does not depend on the ASan runtime library!" >&2
+  exit 1
+fi
+
+# TODO(glider): this doesn't work if we set CC and CXX to override the default
+# Clang.
+ASAN_DYLIB=$(find \
+    "${BUILT_PRODUCTS_DIR}/../../third_party/llvm-build/Release+Asserts/lib/clang/" \
+    -type f -path "*${ASAN_DYLIB_NAME}")
+
+DYLIB_BASENAME=$(basename "${ASAN_DYLIB}")
+if [[ "${DYLIB_BASENAME}" != "${ASAN_DYLIB_NAME}" ]]; then
+  echo "basename(${ASAN_DYLIB}) != ${ASAN_DYLIB_NAME}" >&2
+  exit 1
+fi
+
+# Check whether the directory containing the executable binary is named
+# "MacOS". In this case we're building a full-fledged OSX app and will put
+# the runtime into appname.app/Contents/Libraries/. Otherwise this is probably
+# an iOS gtest app, and the ASan runtime is put next to the executable.
+UPPER_DIR=$(dirname "${BINARY_DIR}")
+if [ "${UPPER_DIR}" == "MacOS" ]; then
+  LIBRARIES_DIR="${UPPER_DIR}/Libraries"
+  mkdir -p "${LIBRARIES_DIR}"
+  NEW_LC_ID_DYLIB="@executable_path/../Libraries/${ASAN_DYLIB_NAME}"
+else
+  LIBRARIES_DIR="${BINARY_DIR}"
+  NEW_LC_ID_DYLIB="@executable_path/${ASAN_DYLIB_NAME}"
+fi
+
+cp "${ASAN_DYLIB}" "${LIBRARIES_DIR}"
+
+# Make LC_ID_DYLIB of the runtime copy point to its location.
+install_name_tool \
+    -id "${NEW_LC_ID_DYLIB}" \
+    "${LIBRARIES_DIR}/${ASAN_DYLIB_NAME}"
+
+# Fix the rpath to the runtime library recorded in the binary.
+install_name_tool \
+    -change "${BUILTIN_DYLIB_PATH}" \
+    "${NEW_LC_ID_DYLIB}" \
+    "${BINARY}"