Added DX SDK search paths to libGLESv2.

Now it builds if these aren't in the default search path.
Should it support x64 targets as well?
Review URL: http://codereview.appspot.com/949041

git-svn-id: https://angleproject.googlecode.com/svn/trunk@175 736b8ea6-26fd-11df-bfd4-992fa37f6226

src/build_angle.gyp

@@ -146,6 +146,7 @@
         'libGLESv2',
         '.',
         '../include',
+        '$(DXSDK_DIR)/include',
       ],
       'sources': [
         'common/angleutils.h',
@@ -186,6 +187,7 @@
       ],
       'msvs_settings': {
         'VCLinkerTool': {
+          'AdditionalLibraryDirectories': ['$(DXSDK_DIR)/lib/x86'],
           'AdditionalDependencies': ['d3dx9.lib'],
         }
       },