Windows native builds fail to find crypto.lib and ssl.lib

[LPardue]

I thought is would be "fun" to try and build quiche natively on Windows. After getting a bunch of perequisites installed (mainly for BoringSSL), I tried cargo build and saw a failure about linking crypto.lib and ssl.lib. A snipped build log

Running `rustc --edition=2018 --crate-name quiche src\lib.rs --color always --crate-type lib --crate-type staticlib --crate-type cdylib --emit=dep-info,link -C debuginfo=2 -C metadata=8d06e7d205e490ea --out-dir C:\Users\lucas\dev\GitHub\quiche\target\debug\deps -C incremental=C:\Users\lucas\dev\GitHub\quiche\target\debug\incremental -L dependency=C:\Users\lucas\dev\GitHub\quiche\target\debug\deps --extern lazy_static=C:\Users\lucas\dev\GitHub\quiche\target\debug\deps\liblazy_static-bb983748a81ac3f1.rlib --extern libc=C:\Users\lucas\dev\GitHub\quiche\target\debug\deps\liblibc-017498fec30aa81b.rlib --extern log=C:\Users\lucas\dev\GitHub\quiche\target\debug\deps\liblog-59ca255ca262bf24.rlib --extern ring=C:\Users\lucas\dev\GitHub\quiche\target\debug\deps\libring-8cd0ab404e521245.rlib -L native=C:\Users\lucas\dev\GitHub\quiche\target\debug\build\quiche-ef19236eef6de95c\out/build/crypto -L native=C:\Users\lucas\dev\GitHub\quiche\target\debug\build\quiche-ef19236eef6de95c\out/build/ssl -l static=crypto -l static=ssl -L native=C:\Users\lucas\dev\GitHub\quiche\target\debug\build\ring-7f8077d125f4de1f\out`

error: could not find native static library `crypto`, perhaps an -L flag is missing?

This seems to be an issue caused by the way Cmake is building BoringSSL. The files are actually dumped into a Debug folder e.g.

C:\Users\lucas\dev\GitHub\quiche\target\debug\build\quiche-ef19236eef6de95c\out/build/ssl/Debug

and for the release build, the output is dumped in a RelWithDebInfo folder e.g.

C:\Users\lucas\dev\GitHub\quiche\target\release\build\quiche-ef19276eef6de95c\out/build/ssl/RelWithDebInfo

Hacking these values manually into src/build.rs lets me do a successful build e.g.

let crypto_dir = format!("{}/build/crypto/RelWithDebInfo", bssl_dir);

However, that is not a viable solution.

[ghedo]

This is probably because of a known bug in the cmake crate rust-lang/cmake-rs#18