http://bugs.winehq.org/show_bug.cgi?id=58286
--- Comment #7 from Ken Sharp imwellcushtymelike@gmail.com --- Running from wine64only does indeed work! Tested with 32-bit and 64-bit programs and everything is back to normal.
Does that make this an invalid bug? The behaviour has changed, apparently. Assuming I was compiling correctly in the first place (I did use the [old] Wiki as a guide).
The documentation (Wiki) does need updating. I'll look at that later if someone doesn't beat me to it. (Please beat me to it)