Add __extension__ for GCC's statement expression.

http://code.google.com/p/google-glog/issues/detail?id=31


git-svn-id: https://google-glog.googlecode.com/svn/trunk@82 eb4d4688-79bd-11dd-afb4-1d65580434c0

src/glog/vlog_is_on.h.in

@@ -80,6 +80,7 @@
 // matching the current source file that represents results of
 // parsing of --vmodule flag and/or SetVLOGLevel calls.
 #define VLOG_IS_ON(verboselevel)                                \
+  __extension__  \
   ({ static @ac_google_namespace@::int32* vlocal__ = &@ac_google_namespace@::kLogSiteUninitialized;           \
      @ac_google_namespace@::int32 verbose_level__ = (verboselevel);                    \
      (*vlocal__ >= verbose_level__) &&                          \

src/windows/glog/vlog_is_on.h

@@ -84,6 +84,7 @@
 // matching the current source file that represents results of
 // parsing of --vmodule flag and/or SetVLOGLevel calls.
 #define VLOG_IS_ON(verboselevel)                                \
+  __extension__  \
   ({ static google::int32* vlocal__ = &google::kLogSiteUninitialized;           \
      google::int32 verbose_level__ = (verboselevel);                    \
      (*vlocal__ >= verbose_level__) &&                          \