random: Fix rndjent for Windows.
* random/jitterentropy-base-user.h [HAVE_W32_SYSTEM] (jent_ncpu): Implement. * random/rndjent.c (_WIN32_WINNT): Define for GetNativeSystemInfo. (EOPNOTSUPP): Define when not available.
- Reported-by: Eli Zaretskii
- GnuPG-bug-id: T5891
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>