manifest load error report.

[Mathieu Othacehe <m.othacehe@gmail.com>]

Hi Guix,

When loading a manifest with an obvious error like "definee
packages-list" instead of "define package-list", no error is reported,
the "guix package -m manifest.scm command just exit with error 1.

When using load instead of load* in a guile repl, the error is correctly
reported :

--8<---------------cut here---------------start------------->8---
/home/mathieu/manifest.scm:1:0: /home/mathieu/manifest.scm:1:0: definee: unbound variable

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
--8<---------------cut here---------------end--------------->8---

Pusing a bit the investigation, it seems that in the pre-unwind-handler
of load* in (guix ui), the "make-stack" call returns #f.

Any idea why ?

Thanks,

Mathieu