Replace xlc __fetch_and_add() with inline asm.
PostgreSQL has been unusable when built with xlc 13 and newer, which are
incompatible with our use of __fetch_and_add(). Back-patch to 9.5,
which introduced pg_atomic_fetch_add_u32().
Reviewed by Tom Lane.
Discussion: https://postgr.es/m/20190831071157.GA3251746@rfd.leadboat.com
Branch
------
REL9_6_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/a1df9a015dac30d467a00f2d42510765d4f0dd5b
Modified Files
--------------
src/include/port/atomics/generic-xlc.h | 39 ++++++++++++++++++++++++++++++----
1 file changed, 35 insertions(+), 4 deletions(-)