api: Add GCRYCTL_AUTO_EXPAND_SECMEM.
* src/gcrypt.h.in (GCRYCTL_AUTO_EXPAND_SECMEM): New enum. * src/global.c (_gcry_vcontrol): Implement that. * src/secmem.c (auto_expand): New var. (_gcry_secmem_set_auto_expand): New. (_gcry_secmem_malloc_internal): Act upon AUTO_EXPAND.
- GnuPG-bug-id: T3530
- Signed-off-by: Werner Koch <wk@gnupg.org>