Move linker settings from standalone.gypi to pdfium.gyp, since they're needed when linking pdfium_t…

pdfium.gyp

Index: pdfium.gyp
diff --git a/pdfium.gyp b/pdfium.gyp
index 9f2cd3d228a69ad2bf8f3f7c4adb0aa9c0cdfc9f..1b0bae01b004e0e7217439d3757d35e71f9ffa7b 100644
--- a/pdfium.gyp
+++ b/pdfium.gyp
@@ -119,7 +119,24 @@
             'fpdfsdk/src/fpdfsdkdll.rc',
           ],
         }],
+        ['OS=="mac"', {
+          'link_settings': {
+            'libraries': [
+              '$(SDKROOT)/System/Library/Frameworks/AppKit.framework',
+              '$(SDKROOT)/System/Library/Frameworks/CoreFoundation.framework',
+            ],
+          },
+        }],
       ],
+      'msvs_settings': {
+        'VCLinkerTool': {
+          'AdditionalDependencies': [
+            'advapi32.lib',
+            'gdi32.lib',
+            'user32.lib',
+          ],
+        },
+      },
     },
     {
       'target_name': 'fdrm',