Wolfgang Walther:
Peter:
I don't think we explicitly offer LTO builds as part of the make build
system, so anyone trying this would do it sort of self-service, by
passing additional options to configure or make. In which case they
might as well pass the -export_dynamic option along in the same way?
The challenge is that it defeats the purpose of LTO to pass this along
to everything, e.g. via CFLAGS. The Makefiles set this in LDFLAGS_EX_BE
only, so it only affects the backend binary. This is not at all obvious
and took me quite a while to figure out why LTO silently didn't strip
symbols from other binaries. It does work to explicitly set
LDFLAGS_EX_BE, though.
Oh, and more importantly: LDFLAGS_EX_BE is not available on all back
branches. It was only introduced in v16 in preparation for meson. So up
to v15, I would have to patch src/makesfiles/Makefile.darwin to set
export_dynamic.
So back-patching a change like this would certainly help to get LTO
across versions seamlessly - which is what I am trying to achieve while
packaging all versions in nixpkgs / NixOS.
Best,
Wolfgang
