[NaCl SDK] Make ARM cross compiler optional until trybots get updated.

native_client_sdk/src/build_tools/build_sdk.py

Index: native_client_sdk/src/build_tools/build_sdk.py
diff --git a/native_client_sdk/src/build_tools/build_sdk.py b/native_client_sdk/src/build_tools/build_sdk.py
index b03e0f5f8dd00ad38d69cac8e7bc997d49946919..6424993b5c36cdcb5c68bc3234aff634e4376af8 100755
--- a/native_client_sdk/src/build_tools/build_sdk.py
+++ b/native_client_sdk/src/build_tools/build_sdk.py
@@ -537,12 +537,15 @@ def GypNinjaBuild(arch, gyp_py_script, gyp_file, targets,
     gyp_defines.append('target_arch=%s' % arch)
     if arch == 'arm':
       if getos.GetPlatform() == 'linux':
-        gyp_env['CC'] = 'arm-linux-gnueabihf-gcc'
-        gyp_env['CXX'] = 'arm-linux-gnueabihf-g++'
-        gyp_env['AR'] = 'arm-linux-gnueabihf-ar'
-        gyp_env['AS'] = 'arm-linux-gnueabihf-as'
-        gyp_env['CC_host'] = 'cc'
-        gyp_env['CXX_host'] = 'c++'
+        if os.path.exists("/usr/bin/arm-linux-gnueabihf-gcc"):

[binji, 2014/01/22 22:33:47]

shouldn't this just skip the arm build entirely instead if the compiler doesn't
exist?

[Sam Clegg, 2014/01/22 22:36:04]

The current nacl gyp files require the arm cross compiler when you in order to
build the nacl_core_sdk gyp target.

There is a NaCl side revert that removes this requirement but I'd
like to put that back once the bots have the compiler installed.

+          # TODO(sbc): make this conditional once all our linux
+          # have the ARM cross compiler installed.
+          gyp_env['CC'] = 'arm-linux-gnueabihf-gcc'
+          gyp_env['CXX'] = 'arm-linux-gnueabihf-g++'
+          gyp_env['AR'] = 'arm-linux-gnueabihf-ar'
+          gyp_env['AS'] = 'arm-linux-gnueabihf-as'
+          gyp_env['CC_host'] = 'cc'
+          gyp_env['CXX_host'] = 'c++'
       gyp_defines += ['armv7=1', 'arm_thumb=0', 'arm_neon=1',
           'arm_float_abi=hard']
       if force_arm_gcc: