pgsql: Further reduce the number of semaphores used under --disable-spi

Further reduce the number of semaphores used under --disable-spinlocks.

Per discussion, there doesn't seem to be much value in having
NUM_SPINLOCK_SEMAPHORES set to 1024: under any scenario where you are
running more than a few backends concurrently, you really had better have a
real spinlock implementation if you want tolerable performance. And 1024
semaphores is a sizable fraction of the system-wide SysV semaphore limit
on many platforms. Therefore, reduce this setting's default value to 128
to make it less likely to cause out-of-semaphores problems.

Branch
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REL9_5_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/c6a5b6677d5f12ccf3c2373117bf630ead30b798

Modified Files
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src/include/pg_config_manual.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)