build: Work around SIZE_MAX bug in OSX headers
commit6b39b06339ee59559b31f860d4af635b046322df
authorEric Blake <eblake@redhat.com>
Tue, 11 Oct 2016 15:46:23 +0000 (11 10:46 -0500)
committerPeter Maydell <peter.maydell@linaro.org>
Tue, 11 Oct 2016 18:22:20 +0000 (11 19:22 +0100)
treecb5fc27fbb900ec671a1bacb8be72d5267e4dba9
parent627eae7d729277c84f8e0ac07a8caab39c92c38d
build: Work around SIZE_MAX bug in OSX headers

C99 requires SIZE_MAX to be declared with the same type as the
integral promotion of size_t, but OSX mistakenly defines it as
an 'unsigned long long' expression even though size_t is only
'unsigned long'.  Rather than futzing around with whether size_t
is 32- or 64-bits wide (which would be needed if we cared about
using SIZE_T in a #if expression), just hard-code it with a cast.
This is not a strict C99-compliant definition, because it doesn't
work in the preprocessor, but if we later need that, the build
will break on Mac to inform us to improve our replacement at that
time.

See also https://patchwork.ozlabs.org/patch/542327/ for an
instance where the wrong type trips us up if we don't fix it
for good in osdep.h.

Some versions of glibc make a similar mistake with SSIZE_MAX; the
goal is that the approach of this patch could be copied to work
around that problem if it ever becomes important to us.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1476200784-17210-1-git-send-email-eblake@redhat.com
Reviewed-by: John Arbuckle <programmingkidx@gmail.com>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
configure
include/qemu/osdep.h