Specify dependences correctly when building mac tools for iOS.

third_party/protobuf/protobuf.gyp

Index: third_party/protobuf/protobuf.gyp
diff --git a/third_party/protobuf/protobuf.gyp b/third_party/protobuf/protobuf.gyp
index 6b060f2d5c6efad576562b588fbc8b5e2580159d..5aa2b4f6b278ee41ea34c014670e49c10ff6c58e 100644
--- a/third_party/protobuf/protobuf.gyp
+++ b/third_party/protobuf/protobuf.gyp
@@ -24,7 +24,47 @@
           'WIN32_LEAN_AND_MEAN',  # Protobuf defines this itself.
         ],
       },
-    }]
+    }],
+    ['OS=="ios"', {
+      'variables': {
+        'ninja_output_dir': 'ninja-protoc',
+        'ninja_product_dir':
+          '<(DEPTH)/xcodebuild/<(ninja_output_dir)/<(CONFIGURATION_NAME)',
+        # Gyp to rerun
+        're_run_targets': [
+          'third_party/protobuf/protobuf.gyp',
+        ],
+      },
+      'targets': [
+        {
+          # On iOS, generating protoc is done via two actions: (1) compiling
+          # the executable with ninja, and (2) copying the executable into a
+          # location that is shared with other projects. These actions are
+          # separated into two targets in order to be able to specify that the
+          # second action should not run until the first action finishes (since
+          # the ordering of multiple actions in one target is defined only by
+          # inputs and outputs, and it's impossible to set correct inputs for
+          # the ninja build, so setting all the inputs and outputs isn't an
+          # option). The first target is given here; the second target is the
+          # normal protoc target under the condition that "OS==iOS".
+          'target_name': 'compile_protoc',
+          'type': 'none',
+          'includes': ['../../build/ios/mac_build.gypi'],
+          'actions': [
+            {
+              'action_name': 'compile protoc',
+              'inputs': [],
+              'outputs': [],
+              'action': [
+                '<@(ninja_cmd)',
+                'protoc',
+              ],
+              'message': 'Generating the C++ protocol buffers compiler',
+            },
+          ],
+        },
+      ],
+    }],
   ],
   'targets': [
     # The "lite" lib is about 1/7th the size of the heavy lib,
@@ -236,26 +276,11 @@
           ],
         }, {  # else, OS=="ios"
           'type': 'none',
-          'variables': {
-            'ninja_output_dir': 'ninja-protoc',
-            # Gyp to rerun
-            're_run_targets': [
-              'third_party/protobuf/protobuf.gyp',
-            ],
-          },
-          'includes': ['../../build/ios/mac_build.gypi'],
+          'dependencies': [
+            'compile_protoc',
+          ],
           'actions': [
             {
-              'action_name': 'compile protoc',
-              'inputs': [],
-              'outputs': [],
-              'action': [
-                '<@(ninja_cmd)',
-                'protoc',
-              ],
-              'message': 'Generating the C++ protocol buffers compiler',
-            },
-            {
               'action_name': 'copy protoc',
               'inputs': [
                 '<(ninja_product_dir)/protoc',