Enables cross-compilation of the VM for ARM.

tools/gyp/configurations_make.gypi

 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 {
   'variables': {
     'arm_cross_libc%': '/opt/codesourcery/arm-2009q1/arm-none-linux-gnueabi/libc',
     'dart_debug_optimization_level%': '2',
   },
   'target_defaults': {
@@ skipping 30 matching lines @@
         'cflags': [ '-m64', '-msse2' ],
         'ldflags': [ '-m64', ],
       },
 
       'Dart_simarm_Base': {
         'cflags': [ '-O3', '-m32', '-msse2' ],
         'ldflags': [ '-m32', ],
       },
 
       'Dart_arm_Base': {
-        'cflags': [
-          '-march=armv7-a',
-          '-mfpu=vfp',
-          '-mfloat-abi=softfp',
-          '-fno-strict-overflow',
-        ],
+        'target_conditions': [
+        ['_toolset=="target"', {
+          'cflags': [
+            '-marm',
+            '-march=armv7-a',
+            '-mfpu=vfp',
+            '-mfloat-abi=softfp',
+            '-Wno-psabi', # suppresses va_list warning
+            '-fno-strict-overflow',
+          ],
+        }],
+        ['_toolset=="host"', {
+          'cflags': ['-m32', '-msse2'],
+          'ldflags': ['-m32'],
+        }]]
       },
 
       'Dart_simmips_Base': {
         'cflags': [ '-O3', '-m32', '-msse2' ],
         'ldflags': [ '-m32', ],
       },
 
       'Dart_mips_Base': {
         'cflags': [
           '-march=mips32r2',
           '-mhard-float',
           '-fno-strict-overflow',
         ],
       },
 
       'Dart_Debug': {
         'cflags': [ '-O<(dart_debug_optimization_level)' ],
       },
 
       'Dart_Release': {
         'cflags': [ '-O3', ],
       },
     },
   },
 }