building locally on windows spawns window for every cl.exe invocation

[wanderview]

I am trying to use sccache2 on my local windows 10 machine. I put this in my mozconfig:

ac_add_options --with-ccache=sccache.exe
export _DEPEND_CFLAGS='-deps$(MDDEPDIR)/$(@F).pp'
mk_add_options "export CC_WRAPPER="
mk_add_options "export CXX_WRAPPER="
mk_add_options "export COMPILE_PDB_FLAG="
mk_add_options "export HOST_PDB_FLAG="
mk_add_options "export MOZ_DEBUG_FLAGS=-Z7"

It seems to be working, but there is a major usability problem. Every invocation of cl.exe spawns a new window. These appear and disappear rapidly changing the focus constantly. This makes the machine pretty useless until the compile ends.

[flxo]

Build sccache with --features=unstable. This will make sccache spawn the compilation in the background.

[luser]

Note that you need to do that with a nightly Rust compiler currently. When Rust 1.16 ships the feature we're using for that will be stable and we can just require Rust 1.16 and use it by default.

[luser]

Also FYI, I have a bug to make simply --with-ccache=path/to/sccache work in the Firefox build system.

[wanderview]

Thanks! Nice to see this getting some investment.