Allow use of global system hooks with API version 2.
* src/libassuan.m4 (LIBASSUAN_API_REQUESTED): New. * src/assuan.h.in (ASSUAN_NO_GLOBAL_SYSTEM_HOOKS_ANY_MORE): New. (ASSUAN_SYSTEM_NPTH_IMPL, ASSUAN_SYSTEM_NPTH): Relax the condition.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>