For an "#if defined(MAP_JIT)" test to work as expected, <sys/mman.h>
must be included in the compilation unit.

Bug: chromium:1144200
Change-Id: Ia0bf35ec1872c02457f1fbc0ee6689c7f7d27d4a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2517689Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70986}