diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index eff6665..ac7c236 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -401,15 +401,13 @@
       "all generators must specify this->FindMakeProgramFile");
     return false;
   }
-  if (!mf->GetDefinition("CMAKE_MAKE_PROGRAM") ||
-      cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
+  if (cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
     std::string setMakeProgram = mf->GetModulesFile(this->FindMakeProgramFile);
     if (!setMakeProgram.empty()) {
       mf->ReadListFile(setMakeProgram);
     }
   }
-  if (!mf->GetDefinition("CMAKE_MAKE_PROGRAM") ||
-      cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
+  if (cmIsOff(mf->GetDefinition("CMAKE_MAKE_PROGRAM"))) {
     std::ostringstream err;
     err << "CMake was unable to find a build program corresponding to \""
         << this->GetName() << "\".  CMAKE_MAKE_PROGRAM is not set.  You "
diff --git a/Source/cmGraphVizWriter.cxx b/Source/cmGraphVizWriter.cxx
index c23156d..8e9abf8 100644
--- a/Source/cmGraphVizWriter.cxx
+++ b/Source/cmGraphVizWriter.cxx
@@ -260,7 +260,7 @@
   do {                                                                        \
     const char* value = mf.GetDefinition(cmakeDefinition);                    \
     if (value) {                                                              \
-      (var) = mf.IsOn(cmakeDefinition);                                       \
+      (var) = cmIsOn(value);                                                  \
     }                                                                         \
   } while (false)