pgsql: Remove configure probes for sys/ipc.h, sys/sem.h, sys/shm.h.

Remove configure probes for sys/ipc.h, sys/sem.h, sys/shm.h.

These are in SUSv2 and every targeted Unix system has them.  It's not
hard to avoid including them on Windows system because they're mostly
used in platform-specific translation units.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA%2BhUKG%2BL_3brvh%3D8e0BW_VfX9h7MtwgN%3DnFHP5o7X2oZucY9dg%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/37a65d1db14658bc75faa3aea7bd5a064118d135

Modified Files
--------------
config/c-library.m4                | 5 +----
configure                          | 7 ++-----
configure.ac                       | 3 ---
src/backend/port/sysv_sema.c       | 6 +-----
src/backend/port/sysv_shmem.c      | 8 ++------
src/backend/storage/ipc/dsm_impl.c | 6 +-----
src/include/pg_config.h.in         | 9 ---------
src/tools/msvc/Solution.pm         | 3 ---
8 files changed, 7 insertions(+), 40 deletions(-)