Prepare switching arm cross-compile to ninja.

build/standalone.gypi

 # Copyright 2012 the V8 project authors. All rights reserved.
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 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
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@@ skipping 1197 matching lines @@
         ['CC.host', '$(CC)'],
         ['CXX.host', '$(CXX)'],
       ],
     }],
     ['clang==1 and OS=="win"', {
       'make_global_settings': [
         # On Windows, gyp's ninja generator only looks at CC.
         ['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.
     ['use_goma==1 and ("<(GENERATOR)"=="ninja" or clang==1)', {
       'make_global_settings': [
        ['CC_wrapper', '<(gomadir)/gomacc'],
        ['CXX_wrapper', '<(gomadir)/gomacc'],
        ['CC.host_wrapper', '<(gomadir)/gomacc'],
        ['CXX.host_wrapper', '<(gomadir)/gomacc'],
       ],
@@ skipping 95 matching lines @@
               '-fsanitize=cfi-vcall',
               '-fsanitize=cfi-derived-cast',
               '-fsanitize=cfi-unrelated-cast',
             ],
           }],
         ],
       },
     }],
   ],
 }