Specify dependences correctly when building mac tools for iOS.

third_party/protobuf/protobuf.gyp

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'conditions': [
     ['OS!="win"', {
       'variables': {
         'config_h_dir':
           '.',  # crafted for gcc/linux.
       },
     }, {  # else, OS=="win"
       'variables': {
         'config_h_dir':
           'vsprojects',  # crafted for msvc.
       },
       'target_defaults': {
         'msvs_disabled_warnings': [
           4018,  # signed/unsigned mismatch in comparison
           4244,  # implicit conversion, possible loss of data
           4355,  # 'this' used in base member initializer list
         ],
         'defines!': [
           '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,
     # but it doesn't support some of the more exotic features of
     # protobufs, like reflection.  To generate C++ code that can link
     # against the lite version of the library, add the option line:
     #
     #   option optimize_for = LITE_RUNTIME;
     #
     # to your .proto file.
@@ skipping 191 matching lines @@
           ],
           'dependencies': [
             'protobuf_full_do_not_use',
           ],
           'include_dirs': [
             '<(config_h_dir)',
             'src/src',
           ],
         }, {  # 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',
               ],
               'outputs': [
                 '<(PRODUCT_DIR)/protoc',
               ],
               'action': [
                 'cp',
                 '<(ninja_product_dir)/protoc',
@@ skipping 82 matching lines @@
   #     ],
   #     'dependencies': [
   #       'protoc#host',
   #     ],
   #     'sources': [
   #       'src/google/protobuf/descriptor.proto',
   #     ],
      },
   ],
 }