Fix Clang build on Android.

build/android/envsetup.sh

 #!/bin/bash
 
 # Copyright (c) 2012 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.
 
 # Sets up environment for building Chromium on Android.  It can either be
 # compiled with the Android tree or using the Android SDK/NDK. To build with
 # NDK/SDK: ". build/android/envsetup.sh --sdk".  Environment variable
 # ANDROID_SDK_BUILD=1 will then be defined and used in the rest of the setup to
@@ skipping 86 matching lines @@
 
 export CC_target="${ANDROID_GOMA_WRAPPER} $(echo -n ${ANDROID_TOOLCHAIN}/*-gcc)"
 export CXX_target="${ANDROID_GOMA_WRAPPER} \
   $(echo -n ${ANDROID_TOOLCHAIN}/*-g++)"
 export LINK_target=$(echo -n ${ANDROID_TOOLCHAIN}/*-gcc)
 export AR_target=$(echo -n ${ANDROID_TOOLCHAIN}/*-ar)
 
 # Performs a gyp_chromium run to convert gyp->Makefile for android code.
 android_gyp() {
   echo "GYP_GENERATORS set to '$GYP_GENERATORS'"
-  "${CHROME_SRC}/build/gyp_chromium" --depth="${CHROME_SRC}" --check "$@"
+  # http://crbug.com/143889.
+  # In case we are doing a Clang build, we have to unset CC_target and
+  # CXX_target. Otherwise GYP ends up generating a gcc build (although we set
+  # 'clang' to 1). This behavior was introduced by
+  # 54d2f6fe6d8a7b9d9786bd1f8540df6b4f46b83f in GYP.
+  (
+    # Fork to avoid side effects on the user's environment variables.
+    if echo "$GYP_DEFINES" | tr ' ' '\n' | grep -q '^clang=' | tail -n1 | \
+        grep -xq clang=1; then
+      if echo "$CC_target" | grep -q gcc; then
+        unset AR_target

[Yaron, 2012/09/04 17:16:19]

Note that I'm actually planning to remove the *_target declarations from
envsetup at some point in the near future. At least for make/ninja they're not
necessary anymore except for one place in v8. If we can clean that up then we
don't need to set or unset these as and can rely on gyp for everything. As this
is temporary, it seems reasonable for now. (also if you want to fix the
underlying issue let me know and I can point you at it :)

[Philippe, 2012/09/05 15:23:24]

Yes that sounds good, please assign the underlying bug to me :). For now let's
keep this (with the approach suggested by Sam).

+        unset CC_target
+        unset CXX_target
+      fi
+    fi
+    "${CHROME_SRC}/build/gyp_chromium" --depth="${CHROME_SRC}" --check "$@"
+  )
 }
 
 # FLOCK needs to be null on system that has no flock
 which flock > /dev/null || export FLOCK=