Just a quick note to users of pgenv and anyone else who compiles Postgres on macOS. In macOS 15.4, Apple introduced a new API, strchrnul, which is common from other platforms. As a result attempting to compile Postgres on 15.4 and later will lead to this error:

snprintf.c:414:27: error: 'strchrnul' is only available on macOS 15.4 or newer [-Werror,-Wunguarded-availability-new]
  414 |                         const char *next_pct = strchrnul(format + 1, '%');
      |                                                ^~~~~~~~~
snprintf.c:366:14: note: 'strchrnul' has been marked as being introduced in macOS 15.4 here, but the deployment target is macOS 15.0.0
  366 | extern char *strchrnul(const char *s, int c);
      |              ^
snprintf.c:414:27: note: enclose 'strchrnul' in a __builtin_available check to silence this warning

Tom Lane chased down and committed the fix, which will be in the next releases of Postgres 13-17. It should also go away once macOS 16.0 comes out. But in the meantime, set MACOSX_DEPLOYMENT_TARGET to the current OS release to avoid the error:

export MACOSX_DEPLOYMENT_TARGET="$(sw_vers -productVersion)"

If you use pgenv, you can add it to your configuration. It will need to be added to all the version configs, too, unless they don’t exist and you also set:

PGENV_WRITE_CONFIGURATION_FILE_AUTOMATICALLY=no