Subject: 26.0.90; Silent fail with `rst-compile-pdf-preview'

From: Simen Heggestøyl <[email-masked]>
Date: Wed, 10 Jan 2018 14:57:18 +0100

If either of the `xpdf' or `rst2pdf' programs are missing,
`rst-compile-pdf-preview' fails without leaving any message. It would be
useful if the command informed the user what's stopping it from working.

-- Simen