[Compilation] Add additional information to compile with unsupported SSL

Author: Warrows

configure.ac

@@ -795,8 +795,8 @@ fi
 AC_CHECK_LIB([crypto],[RAND_egd],[],[
   AC_ARG_WITH([unsupported-ssl],
     [AS_HELP_STRING([--with-unsupported-ssl],[Build with system SSL (default is no; DANGEROUS; NOT SUPPORTED; You should use OpenSSL 1.0)])],
-    [AC_MSG_WARN([Detected unsupported SSL version: This is NOT supported, and may break consensus compatibility!])],
-    [AC_MSG_ERROR([Detected unsupported SSL version: This is NOT supported, and may break consensus compatibility!])]
+    [AC_MSG_WARN([Detected unsupported SSL version: This is NOT supported, and may break consensus compatibility! Use '--with-unsupported-ssl' if you don't care])],
+    [AC_MSG_ERROR([Detected unsupported SSL version: This is NOT supported, and may break consensus compatibility! Use '--with-unsupported-ssl' if you don't care])]
   )
 ])