cmGlobalGenerator: Make IsMultiConfig() const

Source/cmGlobalGenerator.h

@@ -319,7 +319,7 @@ public:
 
   /** Return true if the generated build tree may contain multiple builds.
       i.e. "Can I build Debug and Release in the same tree?" */
-  virtual bool IsMultiConfig() { return false; }
+  virtual bool IsMultiConfig() const { return false; }
 
   std::string GetSharedLibFlagsForLanguage(std::string const& lang) const;
 

Source/cmGlobalVisualStudioGenerator.h

@@ -85,7 +85,7 @@ public:
 
   /** Return true if the generated build tree may contain multiple builds.
       i.e. "Can I build Debug and Release in the same tree?" */
-  virtual bool IsMultiConfig() { return true; }
+  virtual bool IsMultiConfig() const { return true; }
 
   /** Return true if building for Windows CE */
   virtual bool TargetsWindowsCE() const { return false; }

Source/cmGlobalXCodeGenerator.cxx

@@ -3437,7 +3437,7 @@ std::string cmGlobalXCodeGenerator::ComputeInfoPListLocation(
 
 // Return true if the generated build tree may contain multiple builds.
 // i.e. "Can I build Debug and Release in the same tree?"
-bool cmGlobalXCodeGenerator::IsMultiConfig()
+bool cmGlobalXCodeGenerator::IsMultiConfig() const
 {
   // Old Xcode 1.5 is single config:
   if (this->XcodeVersion == 15) {

Source/cmGlobalXCodeGenerator.h

@@ -79,7 +79,7 @@ public:
 
   /** Return true if the generated build tree may contain multiple builds.
       i.e. "Can I build Debug and Release in the same tree?" */
-  virtual bool IsMultiConfig();
+  virtual bool IsMultiConfig() const;
 
   virtual bool SetGeneratorToolset(std::string const& ts, cmMakefile* mf);
   void AppendFlag(std::string& flags, std::string const& flag);