@@ -155,21 +155,25 @@
 ])
 
 objc_runtime="ObjFW runtime"
 AC_CHECK_HEADER(objc/objc.h)
 AC_MSG_CHECKING(which Objective C runtime to use)
-AS_IF([test x"$ac_cv_header_objc_objc_h" = x"yes"], [
-	dnl TODO: This is ugly. Let's think of a better check.
-	AC_EGREP_CPP(yes, [
-		#import <objc/objc.h>
-		#ifdef __objc_INCLUDE_GNU
-		yes
-		#endif
-	], [
-		dnl We don't want the GNU runtime
-	], [
-		objc_runtime="Apple runtime"
+AC_ARG_ENABLE(runtime,
+	AS_HELP_STRING([--enable-runtime], [use the included runtime]))
+AS_IF([test x"$enable_runtime" != x"yes"], [
+	AS_IF([test x"$ac_cv_header_objc_objc_h" = x"yes"], [
+		dnl TODO: This is ugly. Let's think of a better check.
+		AC_EGREP_CPP(yes, [
+			#import <objc/objc.h>
+			#ifdef __objc_INCLUDE_GNU
+			yes
+			#endif
+		], [
+			dnl We don't want the GNU runtime
+		], [
+			objc_runtime="Apple runtime"
+		])
 	])
 ])
 AC_MSG_RESULT($objc_runtime)
 
 case $objc_runtime in
@@ -176,10 +180,13 @@
 	"ObjFW runtime")
 		AC_DEFINE(OF_OBJFW_RUNTIME, 1,
 			[Whether we use the ObjFW runtime])
 		AC_SUBST(GNU_RUNTIME, "-fgnu-runtime")
 		OBJCFLAGS="$OBJCFLAGS -fgnu-runtime"
+
+		AX_CHECK_COMPILER_FLAGS(-fno-objc-nonfragile-abi, [
+			OBJCFLAGS="$OBJCFLAGS -fno-objc-nonfragile-abi"])
 
 		AC_SUBST(RUNTIME, "runtime")
 		if test x"$enable_shared" != x"no"; then
 			AC_SUBST(RUNTIME_LIB_A, "runtime.lib.a")
 			AC_SUBST(RUNTIME_RUNTIME_LIB_A, "runtime/runtime.lib.a")
@@ -209,12 +216,14 @@
 
 case "$host_os" in
 	darwin*)
 		AC_SUBST(REEXPORT_LIBOBJC, ["-Wl,-reexport-lobjc"])
 		AC_SUBST(LDFLAGS_REEXPORT, ["-Wl,-reexport-lobjfw"])
-		AC_SUBST(MACH_ALIAS_LIST,
-			 ["-Xarch_x86_64 -Wl,-alias_list,mach_alias_list"])
+		AS_IF([test x"$objc_runtime" = x"Apple runtime"], [
+			tmp="-Xarch_x86_64 -Wl,-alias_list,mach_alias_list"
+			AC_SUBST(MACH_ALIAS_LIST, $tmp)
+		])
 		;;
 esac
 
 AC_C_BIGENDIAN([
 	AC_DEFINE(OF_BIG_ENDIAN, 1, [Whether we are big endian])