@@ -148,10 +148,13 @@
 objc_runtime="ObjFW runtime"
 AC_CHECK_HEADER(objc/objc.h)
 AC_MSG_CHECKING(which Objective C runtime to use)
 AC_ARG_ENABLE(runtime,
 	AS_HELP_STRING([--enable-runtime], [use the included runtime]))
+AC_ARG_ENABLE(seluid16,
+	AS_HELP_STRING([--enable-seluid16],
+		[use only 16 bit for selectors UIDs]))
 AS_IF([test x"$enable_runtime" != x"yes"], [
 	AS_IF([test x"$ac_cv_header_objc_objc_h" = x"yes"], [
 		dnl TODO: This is ugly. Let's think of a better check.
 		AC_EGREP_CPP(yes, [
 			#import <objc/objc.h>
@@ -212,10 +215,15 @@
 				AC_SUBST(LOOKUP_S, lookup-x86-elf.S)
 				AC_DEFINE(OF_ASM_LOOKUP, 1,
 					[Whether to use lookup in assembly])
 			])
 		])
+
+		AS_IF([test x"$enable_seluid16" = x"yes"], [
+			AC_DEFINE(OF_SELUID16, 1,
+				[Whether to use 16 bit selector UIDs])
+		])
 		;;
 	"Apple runtime")
 		AC_DEFINE(OF_APPLE_RUNTIME, 1,
 			[Whether we use the Apple ObjC runtime])