diff --git a/config.mak.uname b/config.mak.uname
index d56613a139..d916d1dc7a 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -271,6 +271,7 @@ ifeq ($(uname_S),AIX)
 	INTERNAL_QSORT = UnfortunatelyYes
 	NEEDS_LIBICONV = YesPlease
 	BASIC_CFLAGS += -D_LARGE_FILES
+	FILENO_IS_A_MACRO = UnfortunatelyYes
 	ifeq ($(shell expr "$(uname_V)" : '[1234]'),1)
 		NO_PTHREADS = YesPlease
 	else