bug#25360: File mode specification errors during building

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@users.sourceforge.net>
> Date: Mon, 6 Mar 2017 14:56:35 -0500
> Cc: Eli Zaretskii <eliz@gnu.org>, 25360@debbugs.gnu.org
> 
> This still fails on Windows with
> 
>   GEN      ../../lisp/net/tramp-loaddefs.el
> Symbol's function definition is void: w32-convert-standard-filename
> make[2]: *** [Makefile:404: ../../lisp/net/tramp-loaddefs.el] Error 127
> 
> After reverting 1b9463051823 "Remove conditional includes from
> bootstrap" and deleting bootstrap-emacs.exe, I was able to build
> successfully.

Hmm... I don't get it: why did that commit make Emacs bypass loading
important packages when invoked with "loadup bootstrap"?  Phillip, can
you explain the rationale?