Use C++11 override instead of CM_OVERRIDE

We now require C++11 support including `override`.  Drop use of
the old compatibility macro.  Convert references as follows:

    git grep -l CM_OVERRIDE -- '*.h' '*.hxx' '*.cxx' |
      xargs sed -i 's/CM_OVERRIDE/override/g'

1 files changed, 1 insertions, 1 deletions

diff --git a/Source/cmExternalMakefileProjectGenerator.h b/Source/cmExternalMakefileProjectGenerator.h
index 6b89037..a1734ee 100644
--- a/Source/cmExternalMakefileProjectGenerator.h
+++ b/Source/cmExternalMakefileProjectGenerator.h
@@ -99,7 +99,7 @@ public:
   }
 
   cmExternalMakefileProjectGenerator* CreateExternalMakefileProjectGenerator()
-    const CM_OVERRIDE
+    const override
   {
     T* p = new T;
     p->SetName(GetName());