modules: support _ symbol prefix requirement for dlsym.

* configure.ac (LT_FUNC_DLSYM_USCORE): Call it to set NEED_USCORE.
* m4/module.c (uscore_sym): New function.  Use this to prepend an
underscore if NEED_USCORE was set at configure time.
Reported by KO Myung-Hun

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
2 files changed