https://bugs.winehq.org/show_bug.cgi?id=14838
--- Comment #7 from André H. nerv@dawncrow.de --- It's now used in three places: https://source.winehq.org/git/wine.git/commitdiff/613d1715a4f7663f7f160d8260... https://source.winehq.org/git/wine.git/commitdiff/20006966ab737e3da0ed107cf0... https://source.winehq.org/git/wine.git/commitdiff/b5eec8131507773eb6688b84e9...
The winebuild patch was most likely rejected for adding complexity... The libwine patch was rejected because: "The server dir needs to be unique for a given prefix, so it cannot depend on environment variables."
So, this might be a WONTFIX!?