Remove opts from default build - they must now be explicitly built.

Don't crash if objc_disposeClassPair() is called on a class that is not get
registered with the runtime.

GNUmakefile

@@ -120,14 +120,14 @@ endif
 include $(GNUSTEP_MAKEFILES)/aggregate.make
 include $(GNUSTEP_MAKEFILES)/library.make
 
-all::
+build-opts:
 	@echo Building LLVM optimisation passes...
 	@sh build_opts.sh $(MAKE) all
 
-install::
+install-opts: build_opts
 	@echo Installing LLVM optimisation passes...
 	@sh build_opts.sh $(MAKE) install
 
-clean::
+clean-opts:
 	@echo Cleaning LLVM optimisation passes...
 	@sh build_opts.sh $(MAKE) clean

runtime.c

@@ -534,6 +534,8 @@ static void freeIvarLists(Class aClass)
  */
 static inline void safe_remove_from_subclass_list(Class cls)
 {
+	// If this class hasn't been added to the class hierarchy, then this is easy
+	if (!objc_test_class_flag(cls, objc_class_flag_resolved)) { return; }
 	Class sub = cls->super_class->subclass_list;
 	if (sub == cls)
 	{
@@ -569,8 +571,14 @@ void objc_disposeClassPair(Class cls)
 	freeMethodLists(cls);
 	freeMethodLists(meta);
 	freeIvarLists(cls);
-	free_dtable(cls->dtable);
-	free_dtable(meta->dtable);
+	if (cls->dtable != uninstalled_dtable)
+	{
+		free_dtable(cls->dtable);
+	}
+	if (meta->dtable != uninstalled_dtable)
+	{
+		free_dtable(meta->dtable);
+	}
 
 	// Free the class and metaclass
 	free(meta);