pgsql: Be conservative about alignment requirements of struct epoll_eve

Be conservative about alignment requirements of struct epoll_event.

Use MAXALIGN size/alignment to guarantee that later uses of memory are
aligned correctly. E.g. epoll_event might need 8 byte alignment on some
platforms, but earlier allocations like WaitEventSet and WaitEvent might
not sized to guarantee that when purely using sizeof().

Found by myself while testing on an Sun Ultra 5 (Sparc IIi) with some
editorializing by Andres Freund.

In passing fix a couple typos in the area

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/a3b30763cc8686f5b4cd121ef0bf510c1533ac22

Modified Files
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src/backend/storage/ipc/latch.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)