- Re-order dependencies in examples Cargo.toml
- Make sure that GL is tested in reftests
- Remove cfg_aliases `use` from `build.rs`
- Make surfman take precedence over glutin when both features are
enabled.
- Remove unused winit dependency
- Only include winapi when using the `wgl` feature
- Take out DEPTH and STENCIL flags from GL context
- Remove unnecessary drop() call
- Remove unneeded GL `cfg_attr`'s from warden
* GNU Make 4.2
* Windows 10
* PowerShell
```ps
PS C:\Users\okr\gfx> make check
#Note: excluding `warden` here, since it depends on serialization
process_begin: CreateProcess(NULL, #Note: excluding `warden` here, since it depends on serialization, ...) failed.
make (e=2): Das System kann die angegebene Datei nicht finden.
make: *** [makefile:49: check] Error 2
```