quiet down more third-party warnings

gyp/poppler.gyp

 # GYP for libpoppler, a PDF rendering library.
 #
 # !!! WARNING !!! Poppler is GPL software, and should not be used in anything
 # except testing code. Or the lawyercats won't be happy.
 #
 # libpoppler should be statically linked (doesn't have DLL exports),
 # but libpopper-cpp can be dynamically linked.
 
 {
   'variables': {
@@ skipping 108 matching lines @@
         '../third_party/externals/poppler/splash/SplashT1FontEngine.cc',
         '../third_party/externals/poppler/splash/SplashT1FontFile.cc',
         '../third_party/externals/poppler/splash/SplashXPath.cc',
         '../third_party/externals/poppler/splash/SplashXPathScanner.cc',
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '../third_party/externals/poppler/poppler',
         ],
       },
+      'cflags': [
+        '-w'
+      ],
       'conditions': [
         ['skia_os == "linux"', {
           'include_dirs': [
             '../third_party/poppler/config/linux',
             '/usr/include/freetype2',
           ],
           'cflags': [
             '-fPIC',
           ],
         }],
@@ skipping 81 matching lines @@
             'iconv.gyp:iconv',
           ],
           'include_dirs': [
             '../third_party/poppler/config/windows',
           ],
         }],
       ],
     },
   ],
 }