pgsql: For PowerPC instruction "addi", use constraint "b".

For PowerPC instruction "addi", use constraint "b".

Without "b", a variant of the tas() code miscompiles on macOS 10.4.
This may also fix a compilation failure involving macOS 10.1.  Today's
compilers have been allocating acceptable registers with or without this
change, but this future-proofs the code by precisely conveying the
acceptable registers.  Back-patch to 9.4 (all supported versions).

Reviewed by Tom Lane.

Discussion: https://postgr.es/m/20191009063900.GA4066266@rfd.leadboat.com

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/083929372e046662957d20b68aacf5e092bb70cb

Modified Files
--------------
src/include/storage/s_lock.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)