diff -Naur wmsystemtray-1.4.orig/configure.ac wmsystemtray-1.4/configure.ac
--- wmsystemtray-1.4.orig/configure.ac	2014-02-23 03:14:09.000000000 +0100
+++ wmsystemtray-1.4/configure.ac	2021-01-03 00:23:12.004713692 +0100
@@ -9,6 +9,7 @@
 AC_SUBST(VERSION)
 
 # Checks for programs.
+AM_PROG_AR
 AC_PROG_AWK
 AC_PROG_CC
 AC_PROG_CC_STDC