Allow testing library to compile (related: https://github.com/nagios-plugins/nagios-plugins/commit/af4f3723508c25d8c96cff2d7f5dc5d0762c1a71)

lib/tests/Makefile.am

@@ -27,7 +27,7 @@ endif
 
 AM_CFLAGS = -g -I$(top_srcdir)/lib -I$(top_srcdir)/gl $(tap_cflags)
 AM_LDFLAGS = $(tap_ldflags) -ltap
-LDADD = $(top_srcdir)/lib/libnagiosplug.a $(top_srcdir)/gl/libgnu.a
+LDADD = $(top_srcdir)/lib/libnagiosplug.a $(top_srcdir)/gl/libgnu.a $(SSLLIBS)
 
 SOURCES = test_utils.c test_disk.c test_tcp.c test_cmd.c test_base64.c test_ini1.c test_ini3.c test_opts1.c test_opts2.c test_opts3.c