GitLab

(doc-view-ghostscript-program, doc-view-dvipdfm-program)
(doc-view-dvipdf-program, doc-view-unoconv-program)
(doc-view-ps2pdf-program, doc-view-pdftotext-program):
Avoid nil or absolute file name as default value.
(doc-view-pdf->txt, doc-view-ps->pdf): Use executable-find here.