cmGeneratorTarget: Remove outdated const/mutable pair

Source/cmGeneratorTarget.cxx

@@ -5025,7 +5025,7 @@ void cmGeneratorTarget::ComputeTargetManifest(const std::string& config) const
   }
 }
 
-bool cmGeneratorTarget::ComputeCompileFeatures(std::string const& config) const
+bool cmGeneratorTarget::ComputeCompileFeatures(std::string const& config)
 {
   // Compute the language standard based on the compile features.
   cmStandardLevelResolver standardResolver(this->Makefile);
@@ -5063,7 +5063,7 @@ bool cmGeneratorTarget::ComputeCompileFeatures(std::string const& config) const
 }
 
 bool cmGeneratorTarget::ComputeCompileFeatures(
-  std::string const& config, std::set<LanguagePair> const& languagePairs) const
+  std::string const& config, std::set<LanguagePair> const& languagePairs)
 {
   for (const auto& language : languagePairs) {
     BTs<std::string> const* generatorTargetLanguageStandard =

Source/cmGeneratorTarget.h

@@ -613,12 +613,11 @@ public:
   /** Add the target output files to the global generator manifest.  */
   void ComputeTargetManifest(const std::string& config) const;
 
-  bool ComputeCompileFeatures(std::string const& config) const;
+  bool ComputeCompileFeatures(std::string const& config);
 
   using LanguagePair = std::pair<std::string, std::string>;
-  bool ComputeCompileFeatures(
-    std::string const& config,
-    std::set<LanguagePair> const& languagePairs) const;
+  bool ComputeCompileFeatures(std::string const& config,
+                              std::set<LanguagePair> const& languagePairs);
 
   /**
    * Trace through the source files in this target and add al source files
@@ -1241,7 +1240,7 @@ private:
   bool GetRPATH(const std::string& config, const std::string& prop,
                 std::string& rpath) const;
 
-  mutable std::map<std::string, BTs<std::string>> LanguageStandardMap;
+  std::map<std::string, BTs<std::string>> LanguageStandardMap;
 
   cmValue GetPropertyWithPairedLanguageSupport(std::string const& lang,
                                                const char* suffix) const;