Ninja: enable Ninja for CodeBlocks

Source/cmExtraCodeBlocksGenerator.cxx

@@ -59,6 +59,9 @@ cmExtraCodeBlocksGenerator::cmExtraCodeBlocksGenerator()
   this->SupportedGlobalGenerators.push_back("NMake Makefiles");
 // disable until somebody actually tests it:
 //  this->SupportedGlobalGenerators.push_back("MSYS Makefiles");
+#endif
+#ifdef CMAKE_USE_NINJA
+  this->SupportedGlobalGenerators.push_back("Ninja");
 #endif
   this->SupportedGlobalGenerators.push_back("Unix Makefiles");
 }