Horton

Annoying build warnings from latest Apple toolchain

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-hackers@lists.postgresql.org
Date: 2023-09-26T22:23:18Z
Lists: pgsql-hackers 
Since updating to Xcode 15.0, my macOS machines have been
spitting a bunch of linker-generated warnings.  There
seems to be one instance of

ld: warning: -multiply_defined is obsolete

for each loadable module we link, and some program links complain

ld: warning: ignoring duplicate libraries: '-lpgcommon', '-lpgport'

You can see these in the build logs for both sifaka [1] and
indri [2], so MacPorts isn't affecting it.

I'd held out some hope that this was a transient problem due to
the underlying OS still being Ventura, but I just updated another
machine to shiny new Sonoma (14.0), and it's still doing it.
Guess we gotta do something about it.

We used to need "-multiply_defined suppress" to suppress other
linker warnings.  I tried removing that from the Makefile.shlib
recipes for Darwin, and those complaints go away while no new
ones appear, so that's good --- but I wonder whether slightly
older toolchain versions will still want it.

As for the duplicate libraries, yup guilty as charged, but
I think we were doing that intentionally to satisfy some other
old toolchains.  I wonder whether removing the duplication
will create new problems.

			regards, tom lane

[1] https://buildfarm.postgresql.org/cgi-bin/show_stage_log.pl?nm=sifaka&dt=2023-09-26%2021%3A09%3A01&stg=build
[2] https://buildfarm.postgresql.org/cgi-bin/show_stage_log.pl?nm=indri&dt=2023-09-26%2021%3A42%3A17&stg=build

Commits

  1. meson: macos: Avoid warnings on Sonoma

  2. Restore proper linkage of pg_char_to_encoding() and friends.

  3. meson: macos: Correct -exported_symbols_list syntax for Sonoma compat

  4. Suppress macOS warnings about duplicate libraries in link commands.

  5. Stop using "-multiply_defined suppress" on macOS.

  6. Fix the inadvertent libpq ABI breakage discovered by Martin Pitt: the

  7. Cause libpq and ecpg libraries to be built as proper shared libraries