meson: macos: Correct -exported_symbols_list syntax for Sonoma compat

meson: macos: Correct -exported_symbols_list syntax for Sonoma compat

-exported_symbols_list=... works on Ventura and earlier, but not on
Sonoma. The easiest way to fix it is to -Wl,-exported_symbols_list,@0@ which
actually seems more appropriate anyway, it's obviously a linker argument. It
is easier to use the -Wl,, syntax than passing multiple arguments, due to the
way the export_fmt is used (a single string that's formatted), but if it turns
out to be necessary, we can go for multiple arguments as well.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/20230928222248.jw6s7yktpfsfczha@alap3.anarazel.de
Backpatch: 16-, where the meson based buildsystem was added