core: Use gpgrt locking for thread safeness
* configure.ac: Require libgpg-error 1.17. No longer check for pthread. * doc/gpgme.texi: Document removed neccessity for thread safe gpgme flavours. * src/sema.h (DEFINE_GLOBAL_LOCK), (DEFINE_STATIC_LOCK, INIT_LOCK, DECLARE_LOCK) (DESTROY_LOCK, LOCK, UNLOCK): Change to gpgrt equivalents. * src/posix-sema.c, src/w32-sema.c: Removed. * src/Makefile.am: Remove libpthread and Update accordingly. * src/ath.c, src/ath.h (ath_mutex_init) (ath_mutex_destroy, ath_mutex_lock, ath_mutex_unlock): Removed. * src/ath.h (ATH_MUTEX_INITIALIZER): Removed. * src/version.c (do_subsystem_inits): sema_subsystem_init is no longer required. * tests/gpg/Makefile.am: Add new threading tests. (t_thread1_LDADD, t_cancel_LDADD): Use just gpgme. * tests/gpg/t-thread-keylist-verify.c, tests/gpg/t-thread-keylist.c: New. * src/gpgme-config.in: Use -lgpgme for thread-model pthread.
Using gpgrt locks instead of pthread locks removes
the neccessity to link pthread directly to gpgme and
have a different, thread safe flavor of gpgme. Now
gpgme is thread-safe if the conditions mentioned
in the doc are met.
As the cpp bindings linked against libgpgme
and not libgpgme-pthread this fixes threading problems
with them.
libgpgme-pthread is removed but gpgme-config still supports
--thread=pthread for compatibility with find scripts.