Add support for building the Dart VM for Android OS.

runtime/vm/vm.gypi

Index: runtime/vm/vm.gypi
diff --git a/runtime/vm/vm.gypi b/runtime/vm/vm.gypi
index ea3b7d3e2e638b2019f23044a5667a2722f0fe3e..108e9c67c535985d8b5566d5a8ae7c5e240e4f6e 100644
--- a/runtime/vm/vm.gypi
+++ b/runtime/vm/vm.gypi
@@ -31,6 +31,14 @@
         '..',
       ],
       'conditions': [
+        ['OS=="android"', {
+          'link_settings': {
+            'libraries': [
+              '-lc',
+              '-lpthread',
+            ],
+          },
+        }],
         ['OS=="linux"', {
           'link_settings': {
             'libraries': [
@@ -43,7 +51,13 @@
           'sources/' : [
             ['exclude', 'gdbjit.cc'],
           ],
-       }]],
+       }],
+       ['dart_want_separate_host_toolset==1', {
+              'toolsets': ['host', 'target'],
+            }, {
+              'toolsets': ['target'],
+            }],
+      ],
     },
     {
       'target_name': 'libdart_lib_withcore',
@@ -73,6 +87,13 @@
       'include_dirs': [
         '..',
       ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
     },
     {
       'target_name': 'libdart_lib',
@@ -89,6 +110,13 @@
       'include_dirs': [
         '..',
       ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
     },
     {
       'target_name': 'generate_corelib_cc_file',
@@ -128,7 +156,14 @@
           ],
           'message': 'Generating ''<(corelib_cc_file)'' file.'
         },
-      ]
+      ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
     },
     {
       'target_name': 'generate_corelib_impl_cc_file',
@@ -168,7 +203,14 @@
           ],
           'message': 'Generating ''<(corelib_impl_cc_file)'' file.'
         },
-      ]
+      ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
     },
     {
       'target_name': 'generate_math_cc_file',
@@ -206,7 +248,14 @@
           ],
           'message': 'Generating ''<(math_cc_file)'' file.'
         },
-      ]
+      ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
     },
     {
       'target_name': 'generate_mirrors_cc_file',
@@ -244,7 +293,14 @@
           ],
           'message': 'Generating ''<(mirrors_cc_file)'' file.'
         },
-      ]
+      ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
+      ],
     },
     {
       'target_name': 'generate_isolate_cc_file',
@@ -282,6 +338,13 @@
           ],
           'message': 'Generating ''<(isolate_cc_file)'' file.'
         },
+      ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host', 'target'],
+        }, {
+          'toolsets': ['target'],
+        }]
       ]
     },
     {
@@ -309,7 +372,14 @@
           ],
           'message': 'Generating ''<(snapshot_test_dat_file)'' file.'
         },
-      ]
+      ],
+      'conditions': [
+        ['dart_want_separate_host_toolset==1', {
+          'toolsets': ['host'],
+        }, {
+          'toolsets': ['target'],
+        }],
+      ],
     },
   ]
 }