The built-in make is a POSIX make tool, which doesn't support
GNU make features.
As we do have GNU make, insert that as "make.exe" in the busybox
directory. Don't do that in the main llvm-mingw bin directory,
which can be used with other environments (e.g. msys2), where the
native make is to be preferred.
This allows running the built busybox on older versions of
Windows that don't support the utf8 manifest. (The utf8 manifest
is supported since Windows 10 update 1903.)
When building with mingw32-make, it prefers executing commands
through "sh.exe" if it is available.
When busybox sh.exe executes "ar", it prefers executing its own
internal tool over a potential external tool found in $PATH.
(This can be avoided by setting 'export BB_OVERRIDE_APPLETS="ar"',
but as this build of busybox is expected to be used with llvm-mingw,
disable the built-in "ar" tool outright.)
According to https://github.com/mstorsjo/llvm-mingw/issues/533,
if OCaml support is detected and the LLVM OCaml bindings are built,
they are attempted to be installed in a path that require root access.
This version fixes catching pointer data types by reference in C++.
This version also fixes throwing C++ exceptions on aarch64 with
a debugger attached to the process.
Finally, this version fixes delayimport calling of C++ methods that
return structs on aarch64.
These builds fail regularly, under mysterious circumstances.
("The hosted runner lost communication with the server. Anything
in your workflow that terminates the runner process, starves it
for CPU/Memory, or blocks its network access can cause this error.")
This usually seems to happen around the build-libcxx.sh step.
This allows overriding which linker to use.
Currently, building LLVM on Ubuntu 25.10 with these scripts fails,
if LLD is available. This, because the GCC on that distribution
produces object files that LLD (and gold) rejects during linking - see
https://github.com/llvm/llvm-project/issues/156667 for details.
By building with --use-linker=bfd, linking does succeed in that
configuration.
Also pass the same option through from build-all.sh.
In this case it's usually an option that wasn't recognized
(although the misrecognized option may have been an earlier
option and the current one may be the intended prefix).
These variable expansions/modifications work the same if the
option "--pgo" is specified - so either we can simplify the
stripping of the "--pgo=" prefix, or we can just skip the check,
similar to the case above with --instrumented.
Martin Storsjö