[llvm-dev] Shipping custom libc++ on MacOS

[Tobias Hieta via llvm-dev]

Hello,

We are working on an application where we want to have full support
for C++17 but still ship on older versions of macOS (10.9/10.10 in
this case). Our plan was to build our own libc++ from llvm and ship it
with the application and then pass "-D_LIBCPP_DISABLE_AVAILABILITY"

This seemed to work fine in internal testing - but then we ran into a
similar issue as the one described here:
https://reviews.llvm.org/D74489#2497044

Now I can patch my copy of libc++ with the upstream fix for this - but
the comment below made me think otherwise:
https://reviews.llvm.org/D74489#2505156

We have run into problem where if you ship your own libc++ the system
frameworks loads the system libc++ and some strange errors happen - we
thought we could work around these issues - but maybe this is just us
being naive.

So I guess my question is - is it possible to ship a custom libc++ in
a .app archive for older versions of macOS in order to use C++17? Or
is my only hope to raise the minimum version of our app and always
link to the system libc++?

Thanks,
Tobias