Fixed locale environment variables for macOS

Build on macOS creates a broken image because /bin/tr observes locale settings for LANG, LC_ALL, LC_CTYPE, LC_COLLATE (according to the tr manpage).

There was a previous fix that sets LANG and LC_CTYPE, but if e.g. LC_ALL is set to en_us.UTF8 the build process still produces a broken image. This fix sets LC_ALL and LC_COLLATE to C as well so a working image is built.

Looks good to me! Thanks for keeping our codebase clean.

However, I'm only a bot - so a human will still have to approve this request.

merged

mentioned in commit 00b4b33b