Replace custom log! implementation with env_logger

[kinetiknz]

This only exists because it was a pain to use other crates inside Gecko when mp4parse was first developed, but now it's easier and we have many existing users of env_logger inside Gecko.

This came up when @bholley asked why we're using this while he was looking at reducing Debug trait use in release logging.

[djg]

Sounds like a good idea.

…

On 26 Jan. 2018 11:45, "Matthew Gregan" ***@***.***> wrote: This only exists because it was a pain to use other crates inside Gecko when mp4parse was first developed, but now it's easier and we have many existing users of env_logger inside Gecko. This came up when @bholley <https://github.com/bholley> asked why we're using this while he was looking at reducing Debug trait use in release logging. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#139>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAJhrWREVQHLMjP3T3EUNRbTlq8y0EvLks5tOS4lgaJpZM4Rtv6l> .

[bholley]

Replacing the existing log! macro to be a no-op eliminates 71 out of 389 remaining Debug impls in libxul.

Once we switch to env_logger, we should use debug! or trace! for anywhere we want {:?}, since those macros get compiled out in release builds.