Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -378,10 +378,13 @@
 esac
 
 AC_C_BIGENDIAN([
 	AC_DEFINE(OF_BIG_ENDIAN, 1, [Whether we are big endian])
 ])
+AS_IF([test x"$ac_cv_c_bigendian" = x"universal"], [
+	AC_DEFINE(OF_UNIVERSAL, 1, [Whether we are building a universal binary])
+])
 
 AC_MSG_CHECKING(for SIZE_MAX)
 AC_EGREP_CPP(yes, [
 	#include <stdint.h>
 	#include <limits.h>
@@ -417,23 +420,27 @@
 	[AC_MSG_ERROR(
 		[Floating point implementation does not conform to IEEE 754!])])
 
 AC_MSG_CHECKING(for floating point endianess)
 fp_endianess="unknown"
-AC_TRY_COMPILE([
-	double endianess = 2.993700760838795055656993580068609688772747263874402942272934826871811872228512759832626847251963763755836687759498519784550143745834860002945223766052808125982053455555265216112722718870586961456110693379343178124592311441022662940307099598578775368547768968914916965731708568179631324904813506101190853720749196062963892799499230635163056742330563321122389331703618066046034494287335316842529021563862331183541255013987734473643350285400060357711238514186776429325214739886098119655678483017894951556639821088508565036657794343031121375178126860889964700274558728491825977274341798997758923017217660272136611938897932105874133412726223468780517578125e-259;
-], [
-], [
-	AS_IF([$EGREP BigEnd conftest.$ac_objext >/dev/null], [
-		AC_DEFINE(OF_FLOAT_BIG_ENDIAN, 1,
-			[Whether floats are big endian])
-		fp_endianess="big endian"
-	], [
-		AS_IF([$EGREP dnEgiB conftest.$ac_objext >/dev/null], [
-			fp_endianess="little endian"
-		])
-	])
+AS_IF([test x"$ac_cv_c_bigendian" != x"universal"], [
+	AC_TRY_COMPILE([
+		double endianess = 2.993700760838795055656993580068609688772747263874402942272934826871811872228512759832626847251963763755836687759498519784550143745834860002945223766052808125982053455555265216112722718870586961456110693379343178124592311441022662940307099598578775368547768968914916965731708568179631324904813506101190853720749196062963892799499230635163056742330563321122389331703618066046034494287335316842529021563862331183541255013987734473643350285400060357711238514186776429325214739886098119655678483017894951556639821088508565036657794343031121375178126860889964700274558728491825977274341798997758923017217660272136611938897932105874133412726223468780517578125e-259;
+	], [
+	], [
+		AS_IF([$EGREP BigEnd conftest.$ac_objext >/dev/null], [
+			AC_DEFINE(OF_FLOAT_BIG_ENDIAN, 1,
+				[Whether floats are big endian])
+			fp_endianess="big endian"
+		], [
+			AS_IF([$EGREP dnEgiB conftest.$ac_objext >/dev/null], [
+				fp_endianess="little endian"
+			])
+		])
+	])
+], [
+	fp_endianess="universal"
 ])
 AC_MSG_RESULT($fp_endianess)
 AS_IF([test x"$fp_endianess" = x"unknown"], [
 	AC_MSG_ERROR(
 		[Floating point implementation does not conform to IEEE 754!])])

Index: src/macros.h
==================================================================
--- src/macros.h
+++ src/macros.h
@@ -36,17 +36,16 @@
 # define OF_UNLIKELY(cond) cond
 # define OF_CONST_FUNC
 #endif
 
 /* Required to build universal binaries on OS X */
-#if __BIG_ENDIAN__ || __LITTLE_ENDIAN__
-# if __BIG_ENDIAN__ && __LITTLE_ENDIAN__
-#  error __BIG_ENDIAN__ and __LITTLE_ENDIAN__ defined!
-# endif
-# undef OF_BIG_ENDIAN
+#ifdef OF_UNIVERSAL
 # if __BIG_ENDIAN__
 #  define OF_BIG_ENDIAN
+#  define OF_FLOAT_BIG_ENDIAN
+# elif !__LITTLE_ENDIAN__
+#  error OF_UNIVERSAL defined, but neither __BIG_ENDIAN__ nor __LITTLE_ENDIAN__!
 # endif
 #endif
 
 #ifdef OF_BIG_ENDIAN
 # define OF_BYTE_ORDER_NATIVE OF_BYTE_ORDER_BIG_ENDIAN

Index: src/objfw-defs.h.in
==================================================================
--- src/objfw-defs.h.in
+++ src/objfw-defs.h.in
@@ -21,6 +21,7 @@
 #undef OF_HAVE_SOCKETS
 #undef OF_HAVE_SYMLINK
 #undef OF_HAVE_SYS_SOCKET_H
 #undef OF_HAVE_THREADS
 #undef OF_OBJFW_RUNTIME
+#undef OF_UNIVERSAL
 #undef SIZE_MAX