Automatically install executable with extension .exe on Windows

[ghost]

When the user installs an executable, if the source file ends with .bc or .exe, jbuilder makes sure that the destination ends with .exe. This way executables that are installed in any section are correctly installed with the .exe suffix.

Additionally, Jbuilder now resolves ${libexec:<foo>:<file>} to <foo dir>/<file>.exe if it exists, and <foo dir>/<file> otherwise.

@dra27, can you test this branch?

[dra27]

This is great, thanks - I haven't got anything quickly with which to test the ${libexec:...} part, but the automatic adding of .exe is definitely working for ocamlopt compiled and also for a toploop installed using an install stanza.

[dra27]

This is good to go for me - happy to merge?

[ghost]

yep

[fdopen]

There seems to be something wrong with this commit. The latest js_of_ocaml doesn't compile since this commit:
Multiple rules generated for _build/install/default/bin/jsoo_link.exe

[hhugo]

js_of_ocaml install these explicitly
https://github.com/ocsigen/js_of_ocaml/blob/master/compiler/jbuild#L35

[ghost]

@hhugo, do you install both the version with the .exe suffix and the one without?

[dbuenzli]

I guess it does not, see dbuenzli/vg#16