Include stlport through -isystem instead of -I.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index cec5e9405703eab6fd35aeaf17d67a3ad63db6f3..1d8d5af40fe75c498ddafecde2c0d086f495e1f8 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -3815,16 +3815,6 @@
               '-std=gnu++11',
             ],
           }],
-          ['clang==1 and OS=="android"', {
-            # Android uses stlport, whose include/new defines
-            # `void  operator delete[](void* ptr) throw();`, which
-            # clang's -Wimplicit-exception-spec-mismatch warns about for some
-            # reason -- http://llvm.org/PR16638. TODO(thakis): Include stlport
-            # via -isystem instead.
-            'cflags_cc': [
-              '-Wno-implicit-exception-spec-mismatch',
-            ],
-          }],
           ['clang==1 and clang_use_chrome_plugins==1', {
             'cflags': [
               '<@(clang_chrome_plugins_flags)',
@@ -4429,7 +4419,7 @@
                 ],
               }, { # else: use_system_stlport!=1
                 'cflags': [
-                  '-I<(android_stlport_include)',
+                  '-isystem<(android_stlport_include)',
                 ],
                 'ldflags': [
                   '-L<(android_stlport_libs_dir)',