pgsql: meson: macos: Avoid warnings on Sonoma

meson: macos: Avoid warnings on Sonoma

Starting with the Sonoma toolchain macos' linker emits warnings when the same
library is linked to twice. That's ill considered, as the same library can be
used by multiple subsidiary libraries. Luckily there's a flag to suppress that
warning.

On Ventura meson's default of -Wl,-undefined,dynamic_lookup caused warnings,
which we suppressed with -Wl,-undefined,error. Unfortunately that causes a
warning on Sonoma, which is absurd, as it's documented linker default. To
avoid that warning, only add -Wl,-undefined,error if it does not trigger
warnings. Luckily dynamic_lookup doesn't trigger a warning on Sonoma anymore.

Discussion: https://postgr.es/m/20231201040515.p5bshhhtfru7d3da@awork3.anarazel.de
Backpatch: 16-, where the meson build was added

Branch
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REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/9158e4b9eb9916fa586feb26a6149b59566b78e1

Modified Files
--------------
meson.build | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)