diff --git a/configure.ac b/configure.ac
index 69a185044..f5f4e7717 100755
--- a/configure.ac
+++ b/configure.ac
@@ -188,7 +188,8 @@ AC_CANONICAL_HOST
 dnl Get system canonical name
 AC_DEFINE_UNQUOTED(OS, "${host}", [cpu-machine-OS])
 
-dnl Checks for programs.
+# Silence warning: ar: 'u' modifier ignored since 'D' is the default
+AC_SUBST(AR_FLAGS, [cr])
 
 dnl This defines _ALL_SOURCE for AIX
 CURL_CHECK_AIX_ALL_SOURCE