--- a/configure.ac
+++ b/configure.ac
@@ -46,6 +46,7 @@ AC_PROG_CC
 AC_PROG_CC_C99
 AC_PROG_RANLIB
 AC_PROG_YACC
+AM_PROG_AR
 AM_PROG_LEX
 AS_IF([test "x$LEX" == x],
 	  [AC_MSG_ERROR([A Lex/Flex program is required in order to compile wcalc.])],