GTTF: Enable glibcxx debug mode for Debug builds by default.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 06306c8934aeac77a07635c8091b39a1f54a768c..ca39bce228a95be1e658f50b571bc1574b8dfb5b 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1019,8 +1019,6 @@
     # Profile without optimizing out stack frames when profiling==1.
     'profiling_full_stack_frames%': '0',
 
-    # Enable strict glibc debug mode.
-    'glibcxx_debug%': 0,
     # And if we want to dump symbols for Breakpad-enabled builds.
     'linux_dump_symbols%': 0,
     # And if we want to strip the binary after dumping symbols.
@@ -2042,10 +2040,6 @@
       ['profiling==1', {
         'defines': ['ENABLE_PROFILING=1'],
       }],
-      ['OS=="linux" and glibcxx_debug==1', {
-        'defines': ['_GLIBCXX_DEBUG=1',],
-        'cflags_cc+': ['-g'],
-      }],
       ['remoting==1', {
         'defines': ['ENABLE_REMOTING=1'],
       }],
@@ -2646,6 +2640,13 @@
               }],
             ],
           }],
+          ['OS=="linux" and target_arch!="ia32"', {
+            # Enable libstdc++ debugging facilities to help catch problems
+            # early, see http://crbug.com/65151 .
+            # TODO(phajdan.jr): Should we enable this for all of POSIX?
+            'defines': ['_GLIBCXX_DEBUG=1',],
+            'cflags_cc+': ['-g'],
+          }],
           # Disabled on iOS because it was causing a crash on startup.
           # TODO(michelea): investigate, create a reduced test and possibly
           # submit a radar.