Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -21,12 +21,18 @@
 CPPFLAGS="$CPPFLAGS $OBJCPPFLAGS"
 OBJCFLAGS="$OBJCFLAGS -Wall -fexceptions -fobjc-exceptions"
 OBJCFLAGS="$OBJCFLAGS -fconstant-string-class=OFConstantString"
 
 AX_CHECK_COMPILER_FLAGS(-std=gnu99, [OBJCFLAGS="$OBJCFLAGS -std=gnu99"])
-AX_CHECK_COMPILER_FLAGS([-fgnu89-inline -Werror],
-	[OBJCFLAGS="$OBJCFLAGS -fgnu89-inline"])
+case $OBJC in
+	*clang*)
+		;;
+	*)
+		AX_CHECK_COMPILER_FLAGS([-fgnu89-inline -Werror],
+			[OBJCFLAGS="$OBJCFLAGS -fgnu89-inline"])
+		;;
+esac
 AX_CHECK_COMPILER_FLAGS(-pipe, [OBJCFLAGS="$OBJCFLAGS -pipe"])
 AX_CHECK_COMPILER_FLAGS(-fno-common, [OBJCFLAGS="$OBJCFLAGS -fno-common"])
 AX_CHECK_COMPILER_FLAGS(-fno-constant-cfstrings, [
 	OBJCFLAGS="$OBJCFLAGS -fno-constant-cfstrings"
 	AC_SUBST(NO_CONST_CFSTRINGS, "-fno-constant-cfstrings")