Always use the FreeType headers included in PDFium.

pdfium.gyp

 {
   'variables': {
     'pdf_use_skia%': 0,
     'conditions': [
       ['OS=="linux"', {
         'bundle_freetype%': 0,
       }, {  # On Android there's no system FreeType. On Windows and Mac, only a
             # few methods are used from it.
         'bundle_freetype%': 1,
       }],    
     ],
   },
   'target_defaults': {
     'defines' : [
       '_FPDFSDK_LIB',
       '_NO_GDIPLUS_',  # workaround text rendering issues on Windows
       'OPJ_STATIC',
     ],
+    'include_dirs': [
+      'third_party/freetype/include',
+    ],
     'conditions': [
       ['pdf_use_skia==1', {
         'defines': ['_SKIA_SUPPORT_'],
       }],
       ['bundle_freetype==1', {
-        'include_dirs': [
-          'third_party/freetype/include',
-        ],
         'defines' : [
           'FT2_BUILD_LIBRARY',
         ],
-      }, {
-        'include_dirs' : [
-          '/usr/include/freetype2',
-        ],
       }],
       ['OS=="linux"', {
         'conditions': [
           ['target_arch=="x64"', {
             'defines' : [ '_FX_CPU_=_FX_X64_', ],
             'cflags': [ '-fPIC', ],
           }],
           ['target_arch=="ia32"', {
             'defines' : [ '_FX_CPU_=_FX_X86_', ],
           }],
@@ skipping 825 matching lines @@
         'fpdfsdk/src/fpdftext_embeddertest.cpp',
         'fpdfsdk/src/fpdfview_embeddertest.cpp',
         'testing/embedder_test.cpp',
         'testing/embedder_test.h',
         'testing/fx_string_testhelpers.cpp',
         'testing/fx_string_testhelpers.h',
       ],
     },
   ],
 }