* src/misc.c (my_gpgrt_post_fatal_handler): New.
(_gcry_set_gpgrt_post_log_handler): New.
(map_log_level): New.
(_gcry_logv): Use gcrypt log function unless a handler has been
installed.
* src/global.c (global_init): Install post log handler.
* src/gcrypt.h.in (gcry_set_log_handler): Deprecate.