windows: use proper fallback for ssize_t and use stdint.h for types

stdint.h is available since vs2010 and stdbool.h since vs2013,
so we should be able to just use that these days.
2 jobs for wip-meson in 2 minutes and 9 seconds (queued for 3 seconds)
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passed #63965
build autotools

00:00:54

passed #63966
build meson

00:01:36