-AC_ARG_WITH([winsock],
- [AS_HELP_STRING([--with-winsock], [use winsock (WIN32 systems)])],
- [SYSTEM_LIBS='-lws2_32'],
- [SYSTEM_LIBS='-ldl'])
-AC_SUBST([SYSTEM_LIBS])
+AC_CHECK_LIB([ws2_32], [_head_libws2_32_a], [LIBS="$LIBS -lws2_32"])
+AC_CHECK_LIB([dl], [dlopen], [LIBS="$LIBS -ldl"])
+AC_CHECK_LIB([pthread], [pthread_create], [LIBS="$LIBS -lpthread"])
+AC_CHECK_LIB([ssl], [SSL_read], [LIBS="$LIBS -lssl"])
+AC_CHECK_LIB([crypto], [X509_new], [LIBS="$LIBS -lcrypto"])