Tweak the error message as the generate is in the core binary these days.
diff --git a/objectivec/google/protobuf/Empty.pbobjc.h b/objectivec/google/protobuf/Empty.pbobjc.h
index ff7f384..bace614 100644
--- a/objectivec/google/protobuf/Empty.pbobjc.h
+++ b/objectivec/google/protobuf/Empty.pbobjc.h
@@ -4,7 +4,7 @@
#import "GPBProtocolBuffers.h"
#if GOOGLE_PROTOBUF_OBJC_GEN_VERSION != 30000
-#error This file was generated by a different version of protoc-gen-objc which is incompatible with your Protocol Buffer sources.
+#error This file was generated by a different version of protoc which is incompatible with your Protocol Buffer library sources.
#endif
// @@protoc_insertion_point(imports)