Re: mingw32-make does not find prerequisites in VPATH when they have forward slashes

[Paul Smith]

On Thu, 2016-06-16 at 18:35 -0600, Erasmo Aguilera wrote:
> I am working on a project with two directory trees: one for sources
> and another for output files. I run mingw-make from the source tree
> and add the output tree root to VPATH so that their files can be found
> when acting as prerequisites. But it doesn’t so when such
> prerequisites specify their path from the root with forward slashes.
> It gives me the error “cannot open input file”. However, if I change
> the forward slashes for backslashes, then it works.

I don't know why using different slashes would make a difference.  I
wonder if that's really what made the difference.

Because, the method you're using is not how VPATH is intended to be
used.  VPATH can only be reliably used to locate _source_ files (or in
any event, files that the current make invocation treats as "leaf
targets" that cannot be built).

See: http://make.mad-scientist.net/papers/how-not-to-use-vpath/