@@ -536,12 +536,11 @@
 		AC_SUBST(FOUNDATION_COMPAT_M, "foundation-compat.m")
 	])
 ])
 
 AS_IF([test x"$GOBJC" = x"yes"], [
-	OBJCFLAGS="$OBJCFLAGS -Wwrite-strings -Wcast-align -Wpointer-arith"
-       	OBJCFLAGS="$OBJCFLAGS -Werror"
+	OBJCFLAGS="$OBJCFLAGS -Wwrite-strings -Wpointer-arith -Werror"
 
 	AC_MSG_CHECKING(whether gcc has bug objc/27438)
 	AC_TRY_COMPILE([
 		@interface OFConstantString
 		{
@@ -563,28 +562,53 @@
 		AC_SUBST(NO_WARN_UNUSED, "-Wno-unused-variable")
 	])
 
 	AC_MSG_CHECKING(whether we need -Wno-strict-aliasing due to gcc bugs)
 	AC_TRY_COMPILE([
-		@interface OFObject
+		@interface Foo
 		{
-			Class isa;
+			struct objc_class *isa;
 		}
 		@end
 
 		static struct {
 			struct objc_class *isa;
 		} object;
 	], [
-		OFObject *test = (OFObject*)&object;
+		Foo *test = (Foo*)&object;
 		(void)test; /* Get rid of unused variable warning */
 	], [
 		AC_MSG_RESULT(no)
 	], [
 		AC_MSG_RESULT(yes)
 		OBJCFLAGS="$OBJCFLAGS -Wno-strict-aliasing"
 	])
+
+	old_OBJCFLAGS="$OBJCFLAGS"
+	OBJCFLAGS="$OBJCFLAGS -Wcast-align"
+	AC_MSG_CHECKING(whether -Wcast-align is buggy)
+	AC_TRY_COMPILE([
+		@interface Foo
+		{
+			struct objc_class *isa;
+		}
+		@end
+
+		@implementation Foo
+		- (void)foo
+		{
+			struct objc_class *c = isa;
+			(void)c;
+		}
+		@end
+	], [
+	], [
+		AC_MSG_RESULT(no)
+	], [
+		AC_MSG_RESULT(yes)
+		OBJCFLAGS="$old_OBJCFLAGS"
+	])
 ])
 
 AS_IF([test x"$cross_compiling" = x"yes"], [
 	AC_SUBST(BIN_PREFIX, "$host-")