--- configure.orig	2019-07-12 16:18:37 UTC
+++ configure
@@ -20165,7 +20165,7 @@ if test "x$ax_pthread_clang" = "xyes"; t
 	# ignore this macro, third-party headers might not.)
 
 	PTHREAD_CFLAGS="-pthread"
-	PTHREAD_LIBS=
+	PTHREAD_LIBS="-pthread"
 
 	ax_pthread_ok=yes