diff -ur ORIG/configure.ac MOD/configure.ac
--- ORIG/configure.ac	2020-06-21 13:23:49.051525439 +0200
+++ MOD/configure.ac	2020-06-21 13:24:14.279437637 +0200
@@ -24,6 +24,7 @@
 
 AC_PROG_INSTALL
 AC_PROG_RANLIB
+AM_PROG_AR
 
 dnl test for inline
 AC_C_INLINE