diff --git a/configure.ac b/configure.ac
index 64007f7d..30f9ef0a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -52,6 +52,12 @@ AC_PROG_RANLIB
 AC_PATH_PROG(AR, ar)
 AC_SUBST(AR)
 
+if test "X$AR" = "X"; then
+	AC_MSG_ERROR([
+ar program not found.  Please fix your PATH to include the directory in
+which ar resides, or set AR in the environment with the full path to ar.])
+fi
+
 AC_CONFIG_HEADERS([includes/config.h])
 
 # we sometimes need to know byte order for building packets