Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -190,10 +190,32 @@
 		if test x"$enable_static" = x"yes" \
 		    -o x"$enable_shared" = x"no"; then
 			AC_SUBST(RUNTIME_A, "runtime.a")
 			AC_SUBST(RUNTIME_RUNTIME_A, "runtime/runtime.a")
 		fi
+
+		AC_EGREP_CPP(yes, [
+			#if defined(__amd64__) || defined(__x86_64__)
+			# ifdef __ELF__
+			yes
+			# endif
+			#endif
+		], [
+			AC_SUBST(LOOKUP_S, lookup-amd64-elf.S)
+			AC_DEFINE(OF_ASM_LOOKUP, 1,
+				[Whether to use lookup in assembly])
+		], [
+			AC_EGREP_CPP(yes, [
+				#if defined(__i386__) && defined(__ELF__)
+				yes
+				#endif
+			], [
+				AC_SUBST(LOOKUP_S, lookup-x86-elf.S)
+				AC_DEFINE(OF_ASM_LOOKUP, 1,
+					[Whether to use lookup in assembly])
+			])
+		])
 		;;
 	"Apple runtime")
 		AC_DEFINE(OF_APPLE_RUNTIME, 1,
 			[Whether we use the Apple ObjC runtime])
 

Index: extra.mk.in
==================================================================
--- extra.mk.in
+++ extra.mk.in
@@ -10,10 +10,11 @@
 EXCEPTIONS_A = @EXCEPTIONS_A@
 EXCEPTIONS_EXCEPTIONS_A = @EXCEPTIONS_EXCEPTIONS_A@
 EXCEPTIONS_EXCEPTIONS_LIB_A = @EXCEPTIONS_EXCEPTIONS_LIB_A@
 EXCEPTIONS_LIB_A = @EXCEPTIONS_LIB_A@
 FOUNDATION_COMPAT_M = @FOUNDATION_COMPAT_M@
+LOOKUP_S = @LOOKUP_S@
 MACH_ALIAS_LIST = @MACH_ALIAS_LIST@
 OFBLOCKTESTS_M = @OFBLOCKTESTS_M@
 OBJC_PROPERTIES_M = @OBJC_PROPERTIES_M@
 OBJC_SYNC_M = @OBJC_SYNC_M@
 OFHTTPREQUESTTESTS_M = @OFHTTPREQUESTTESTS_M@

Index: src/runtime/Makefile
==================================================================
--- src/runtime/Makefile
+++ src/runtime/Makefile
@@ -6,12 +6,11 @@
 SRCS = category.m		\
        class.m			\
        hashtable.m		\
        init.m			\
        lookup.m			\
-       lookup-amd64-elf.S	\
-       lookup-x86-elf.S		\
+       ${LOOKUP_S}		\
        property.m		\
        protocol.m		\
        selector.m		\
        sparsearray.m		\
        static-instances.m	\

Index: src/runtime/lookup-amd64-elf.S
==================================================================
--- src/runtime/lookup-amd64-elf.S
+++ src/runtime/lookup-amd64-elf.S
@@ -12,12 +12,10 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
-#if defined(__x86_64__) && defined(__ELF__)
-
 .globl objc_msg_lookup
 .globl objc_msg_lookup_super
 
 .section .text
 objc_msg_lookup:
@@ -66,7 +64,5 @@
 
 .type objc_msg_lookup, @function
 .type objc_msg_lookup_super, @function
 .size objc_msg_lookup, forward-objc_msg_lookup
 .size objc_msg_lookup_super, ret_nil-objc_msg_lookup_super
-
-#endif

Index: src/runtime/lookup-x86-elf.S
==================================================================
--- src/runtime/lookup-x86-elf.S
+++ src/runtime/lookup-x86-elf.S
@@ -12,12 +12,10 @@
  * Public License, either version 2 or 3, which can be found in the file
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
-#if defined(__i386__) && defined(__ELF__)
-
 .globl objc_msg_lookup
 .globl objc_msg_lookup_super
 
 .section .text
 objc_msg_lookup:
@@ -74,7 +72,5 @@
 
 .type objc_msg_lookup, @function
 .type objc_msg_lookup_super, @function
 .size objc_msg_lookup, forward-objc_msg_lookup
 .size objc_msg_lookup_super, ret_nil-objc_msg_lookup_super
-
-#endif

Index: src/runtime/lookup.m
==================================================================
--- src/runtime/lookup.m
+++ src/runtime/lookup.m
@@ -41,11 +41,11 @@
 
 	return (objc_sparsearray_get(cls->dtable, (uint32_t)sel->uid) != NULL
 	    ? YES : NO);
 }
 
-#if !defined(__ELF__) || (!defined(OF_X86_ASM) && !defined(OF_AMD64_ASM))
+#ifndef OF_ASM_LOOKUP
 static id
 nil_method(id self, SEL _cmd)
 {
 	return nil;
 }