--- a/configure.ac
+++ b/configure.ac
@@ -28,6 +28,7 @@ dnl those two are apparently included in AC_CANONICAL_TARGET
 dnl AC_CANONICAL_BUILD
 dnl AC_CANONICAL_HOST
 
+AM_PROG_AR
 AC_PROG_RANLIB
 AM_INIT_AUTOMAKE([subdir-objects tar-ustar])