bug#24956: 26.0.50; On Windows, setting PATH in compilation-environment has no effect

[Óscar Fuentes]

emacs -Q. Evaluate:

(let ((compilation-environment (list "PATH=d:\\foo")))
  (compile "echo %PATH%"))

The output is the original contents of PATH. Until recently (June, at
least) it was possible to set PATH in compilation-environment and pass
it to child processes. On GNU/Linux, it still is.


In GNU Emacs 26.0.50.1 (x86_64-w64-mingw32)
 of 2016-10-17 built on WIN8-64-VM
Repository revision: 032a299b0ed25f067f4133c547a822b283bc4cb8
Windowing system distributor 'Microsoft Corp.', version 6.3.9600