Enable libstdc++ debug mode in debug builds.

For now it's only enabled on Linux/Intel.

R=mstarzinger@chromium.org
BUG=v8:3638
LOG=y

Review URL: https://codereview.chromium.org/650013006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24794 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

build/standalone.gypi

@@ -136,6 +136,14 @@
     'configurations': {
       'DebugBaseCommon': {
         'cflags': [ '-g', '-O0' ],
+        'conditions': [
+          ['(v8_target_arch=="ia32" or v8_target_arch=="x64" or v8_target_arch=="x87") and \
+            OS=="linux"', {
+            'defines': [
+              '_GLIBCXX_DEBUG'
+            ],
+          }],
+        ],
       },
       'Optdebug': {
         'inherit_from': [ 'DebugBaseCommon', 'DebugBase2' ],