cmIDEOptions: Add HasFlag method to test if a flag is set

Source/cmIDEOptions.cxx

@@ -216,6 +216,12 @@ void cmIDEOptions::RemoveFlag(const char* flag)
   this->FlagMap.erase(flag);
 }
 
+//----------------------------------------------------------------------------
+bool cmIDEOptions::HasFlag(std::string const& flag) const
+{
+  return this->FlagMap.find(flag) != this->FlagMap.end();
+}
+
 //----------------------------------------------------------------------------
 const char* cmIDEOptions::GetFlag(const char* flag)
 {

Source/cmIDEOptions.h

@@ -34,6 +34,7 @@ public:
   void AppendFlag(std::string const& flag,
                   std::vector<std::string> const& value);
   void RemoveFlag(const char* flag);
+  bool HasFlag(std::string const& flag) const;
   const char* GetFlag(const char* flag);
 
 protected: