Notify extra generators about languages

Some generators can use the any enabled languages to add extra support
in the relevant build tool. One such is Eclipse since there are many
plugins available for various languages.

Source/cmExternalMakefileProjectGenerator.cxx

@@ -13,6 +13,12 @@
 
 #include "cmExternalMakefileProjectGenerator.h"
 
+void cmExternalMakefileProjectGenerator
+::EnableLanguage(std::vector<std::string> const&,
+                 cmMakefile *, bool)
+{
+}
+
 std::string cmExternalMakefileProjectGenerator::CreateFullGeneratorName(
                                                    const char* globalGenerator,
                                                    const char* extraGenerator)

Source/cmExternalMakefileProjectGenerator.h

@@ -41,6 +41,8 @@ public:
   /** Get the documentation entry for this generator.  */
   virtual void GetDocumentation(cmDocumentationEntry& entry,
                                 const char* fullName) const = 0;
+  virtual void EnableLanguage(std::vector<std::string> const& languages,
+                              cmMakefile *, bool optional);
 
   ///! set the global generator which will generate the makefiles
   virtual void SetGlobalGenerator(cmGlobalGenerator* generator)

Source/cmGlobalGenerator.cxx

@@ -695,6 +695,11 @@ cmGlobalGenerator::EnableLanguage(std::vector<std::string>const& languages,
     {
     mf->ReadListFile(0,projectCompatibility.c_str());
     }
+  // Inform any extra generator of the new language.
+  if (this->ExtraGenerator)
+    {
+    this->ExtraGenerator->EnableLanguage(languages, mf, false);
+    }
 
   if(fatalError)
     {