message: try set mingw path
diff: @@ -9,11 +9,13 @@ environment:
  target: x86_64-pc-windows-msvc
  - channel: nightly
  target: x86_64-pc-windows-gnu
  + msys_bits: 64
  install:
  - appveyor DownloadFile https://win.rustup.rs/ -FileName rustup-init.exe
  - rustup-init -yv --default-toolchain %channel% --default-host %target%
  - set PATH=%PATH%;%USERPROFILE%\.cargo\bin
  + - if defined msys_bits set PATH=%PATH%;C:\msys64\mingw%msys_bits%\bin
  - rustc -vV
  - cargo -vV
  