Add gpgme_set_global_flag to help debugging
* src/gpgme.c (gpgme_set_global_flag): New. * src/gpgme.h.in (gpgme_set_global_flag): New. * src/gpgme.def, src/libgpgme.vers: Add new public function. * src/debug.c (envvar_override): New.: (_gpgme_debug_set_debug_envvar): New. (debug_init): Take ENVVAR_OVERRIDE in account.
On Android envvars can't be used, thus we need another way to enable
GPGME debugging. The new function allows this and may be used in the
future to implement similar things.