Hi guix,

This is version 4 of the patch series.
It lets 'search-input-file' raise the new
&search-error exception instead of misc-error.

The documentation of 'search-input-file' has been
adjusted to give an example of how it can be used.

Also, there is one new test in tests/build-utils.scm
("search-input-file: can search in multiple directories").

Greetings,
Maxime.