diff --git a/GNUmakefile b/GNUmakefile
index 95bd536..1aa1a1d 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -44,6 +44,7 @@ ifneq ($(install_headers), no)
 libobjc_HEADER_FILES = \
 	Availability.h\
 	Object.h\
+	Protocol.h\
 	blocks_runtime.h\
 	capabilities.h\
 	encoding.h\
diff --git a/encoding2.c b/encoding2.c
index 124bebc..924a59a 100644
--- a/encoding2.c
+++ b/encoding2.c
@@ -418,14 +418,13 @@ unsigned objc_get_type_qualifiers (const char *type)
 		switch (*(type++))
 		{
 			default: return flags;
-			// Byref is implicit
-			case 'R': break;
 			MAP('r', 1)
 			MAP('n', 1)
 			MAP('o', 2)
 			MAP('N', 3)
 			MAP('O', 4)
 			MAP('V', 8)
+			MAP('R', 8)
 		}
 	} while (1);
 }
diff --git a/objc/encoding.h b/objc/encoding.h
index 80cabb8..cc8b710 100644
--- a/objc/encoding.h
+++ b/objc/encoding.h
@@ -56,11 +56,14 @@ void objc_layout_structure_get_info (struct objc_struct_layout *layout,
                                      unsigned int *align,
                                      const char **type);
 
-#define _F_IN       0x01
-#define _F_OUT      0x02
-#define _F_INOUT    0x03
-#define _F_BYCOPY   0x04
-#define _F_ONEWAY   0x08
-#define _F_CONST    0x01
+#define _F_CONST       0x01
+#define _F_IN          0x01
+#define _F_OUT         0x02
+#define _F_INOUT       0x03
+#define _F_BYCOPY      0x04
+#define _F_ONEWAY      0x08
+#define _F_BYREF       0x08
+#define _F_ONEWAY      0x10
+#define _F_GCINVISIBLE 0x20
 
 #endif // __LIBOBJC_ENCODING_H_INCLUDED__