Created attachment 521795 [details] [diff] [review]
There is a special case added for mingw to js/src/configure.in that treats mingw differently for mingw in bug 538216 comment 32. It was needed back then. However mingw-w64 (a fork of mingw.org, unlike what name suggests, not win64-specific) uses proper triplet i686-w64-mingw32 in this case. We could improve special-case to detect only plain old mingw, but right now m-c compiles only with mingw-w64 and it is unlikely to change (esp. given that mingw-w64 replacing domination of plain mingw is a matter of time), so I propose to get rid of the special case at all.
Thanks for review, pushed to t-m:
Merged to m-c: