Prepare switching arm cross-compile to ninja.

build/standalone.gypi

Index: build/standalone.gypi
diff --git a/build/standalone.gypi b/build/standalone.gypi
index fa4d45d4eb42f765a8d6fd13c198b270a468185c..985e863ce6382cf9d3c0808740a88d7d15e0a8b3 100644
--- a/build/standalone.gypi
+++ b/build/standalone.gypi
@@ -1215,6 +1215,16 @@
         ['CC', '<(clang_dir)/bin/clang-cl'],
       ],
     }],
+    ['OS=="linux" and target_arch=="arm" and host_arch!="arm" and clang==0', {

[kjellander_chromium, 2015/11/20 08:23:47]

I'm just curious: is host_arch ever arm?

[Michael Achenbach, 2015/11/20 08:26:02]

Guess not. But can't hurt to check. This is a brain-off copy from common.gypi:
https://code.google.com/p/chromium/codesearch#chromium/src/build/common.gypi&...

[Jakob Kummerow, 2015/11/20 09:52:37]

Drive-by answer: yes, we support native compilation on ARM machines.

+      # Set default ARM cross tools on linux.  These can be overridden
+      # using CC,CXX,CC.host and CXX.host environment variables.
+      'make_global_settings': [
+        ['CC', '<!(which arm-linux-gnueabihf-gcc)'],

[martyn.capewell, 2015/11/24 11:56:55]

Does this work if arm-linux-gnueabihf-gcc isn't already in your path? I set CC
externally, but get failures on this which command.

[Michael Achenbach, 2015/11/24 12:27:31]

Hmm, that's not smart of gyp then. I thought it might keep an externally set CC.

Do you use make or ninja? If you use make, we could add "<(GENERATOR)"=="ninja"
to the conditions as a work-around.

+        ['CXX', '<!(which arm-linux-gnueabihf-g++)'],
+        ['CC.host', '<(host_cc)'],
+        ['CXX.host', '<(host_cxx)'],
+      ],
+    }],
     # TODO(yyanagisawa): supports GENERATOR==make
     #  make generator doesn't support CC_wrapper without CC
     #  in make_global_settings yet.