[Bug 48471] Mismatching behavior of GetEnvironmentVariableW for empty / long values

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=48471

--- Comment #3 from Vladimir Panteleev  ---
My latest patch was rejected because I left an old test inconsistent with the
rest of the file:

https://source.winehq.org/patches/data/176822

Upon attempting to fix this, I discovered that the reason the test was that way
was because Wine's GetEnvironmentVariableA hid another inconsistency, in that
it resets GetLastError to NO_ERROR when it doesn't fail, instead of preserving
the error (like Windows and GetEnvironmentVariableW). I guess I will include a
fix for that in the next patch series version.