gpgscm: Add support for pseudo-random numbers.
* tests/gpgscm/ffi.c (do_getpid): New function. (do_srandom): Likewise. (random_scaled): Likewise. (do_random): Likewise. (do_make_random_string): Likewise. (ffi_init): Expose the new functions. * tests/gpgscm/lib.scm: Document the new functions.
- Signed-off-by: Justus Winter <justus@g10code.com>