Extract use_system_foo logic out of gyp files, patch 2

third_party/jsoncpp/jsoncpp.gyp

Index: third_party/jsoncpp/jsoncpp.gyp
diff --git a/third_party/jsoncpp/jsoncpp.gyp b/third_party/jsoncpp/jsoncpp.gyp
index b7125711d3cac42c7dad798d4d49863d5116286a..1395f94bbf093bda189114b31e44869460210116 100644
--- a/third_party/jsoncpp/jsoncpp.gyp
+++ b/third_party/jsoncpp/jsoncpp.gyp
@@ -3,82 +3,41 @@
 # found in the LICENSE file.
 
 {
-  'variables': {
-    'use_system_jsoncpp%': 0,
-  },
-  'conditions': [
-    ['use_system_jsoncpp==0', {
-      'targets': [
-        {
-          'target_name': 'jsoncpp',
-          'type': 'static_library',
-          'defines': [
-            'JSON_USE_EXCEPTION=0',
-          ],
-          'sources': [
-            'source/include/json/assertions.h',
-            'source/include/json/autolink.h',
-            'source/include/json/config.h',
-            'source/include/json/features.h',
-            'source/include/json/forwards.h',
-            'source/include/json/json.h',
-            'source/include/json/reader.h',
-            'overrides/include/json/value.h',
-            'source/include/json/writer.h',
-            'source/src/lib_json/json_batchallocator.h',
-            'source/src/lib_json/json_reader.cpp',
-            'source/src/lib_json/json_tool.h',
-            'overrides/src/lib_json/json_value.cpp',
-            'source/src/lib_json/json_writer.cpp',
-          ],
-          'include_dirs': [
-            'overrides/include/',
-            'source/include/',
-            'source/src/lib_json/',
-          ],
-          'direct_dependent_settings': {
-            'include_dirs': [
-              'overrides/include/',
-              'source/include/',
-            ],
-          },
-        },
+  'targets': [
+    {
+      'target_name': 'jsoncpp',
+      'type': 'static_library',
+      'defines': [
+        'JSON_USE_EXCEPTION=0',
       ],
-    }, { # use_system_jsoncpp==1
-      'targets': [
-        {
-          'target_name': 'jsoncpp',
-          'type': 'none',
-          'variables': {
-            'headers_root_path': 'source/include',
-            'header_filenames': [
-              'json/assertions.h',
-              'json/autolink.h',
-              'json/config.h',
-              'json/features.h',
-              'json/forwards.h',
-              'json/json.h',
-              'json/reader.h',
-              'json/value.h',
-              'json/writer.h',
-            ],
-          },
-          'includes': [
-            '../../build/shim_headers.gypi',
-          ],
-          'direct_dependent_settings': {
-            'include_dirs': [
-              '/usr/include/jsoncpp',
-            ],
-          },
-          'link_settings': {
-            'libraries': [
-              '-ljsoncpp',
-            ],
-          },
-        }
+      'sources': [
+        'source/include/json/assertions.h',
+        'source/include/json/autolink.h',
+        'source/include/json/config.h',
+        'source/include/json/features.h',
+        'source/include/json/forwards.h',
+        'source/include/json/json.h',
+        'source/include/json/reader.h',
+        'overrides/include/json/value.h',
+        'source/include/json/writer.h',
+        'source/src/lib_json/json_batchallocator.h',
+        'source/src/lib_json/json_reader.cpp',
+        'source/src/lib_json/json_tool.h',
+        'overrides/src/lib_json/json_value.cpp',
+        'source/src/lib_json/json_writer.cpp',
       ],
-    }],
+      'include_dirs': [
+        'overrides/include/',
+        'source/include/',
+        'source/src/lib_json/',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [
+          'overrides/include/',
+          'source/include/',
+        ],
+      },
+    },
   ],
 }