Fix module definition file reference for VS6 NMake

When building through NMake with VS 6, the module definition file must
be passed without spaces in the path.  This is because 'cl -link' does
not escape the spaces when passing the value on to the linker.

Source/cmMakefileTargetGenerator.cxx

@@ -1755,10 +1755,10 @@ void cmMakefileTargetGenerator::AddModuleDefinitionFlag(std::string& flags)
     return;
     }
 
-  // Append the flag and value.
+  // Append the flag and value.  Use ConvertToLinkReference to help
+  // vs6's "cl -link" pass it to the linker.
   std::string flag = defFileFlag;
-  flag += this->Convert(this->ModuleDefinitionFile.c_str(),
-                        cmLocalGenerator::START_OUTPUT,
-                        cmLocalGenerator::SHELL);
+  flag += (this->LocalGenerator->ConvertToLinkReference(
+             this->ModuleDefinitionFile.c_str()));
   this->LocalGenerator->AppendFlags(flags, flag.c_str());
 }