BRANCH: created branch barbier
Remove citations from Developers' Guide, they had been dropped by r1900
Generate index in PDF documents

HTML versions of the Developer's Guide, Use Cases Guide,
and User Manual for the Textual User Interface do provide
an index.  Make PDF versions also provide this index.

Escape underscores in index entries.
Fix sorting of keywords extracted from code listings.
Remove index duplicates.

distcheck ok.
Fix links to external documents in PDF files

This patch relies on refcount and xr-hyper LaTeX packages to load references to
external documents so that linked PDF file is opened at the right page.  This
is supported only by few PDF viewers though.

There is no cyclic dependency, we can build ReferenceGuide, UserManual and
UseCasesGuide in this order.

distcheck ok.
Fix races with parallel builds

Move \externaldocument away from otcommon.sty, otherwise all pdflatex
calls read .aux files, which may cause races.
Declare explicit dependencies between ReferenceGuide, UseCasesGuide and
UserManual to ensure that required .aux files exist when needed.

distcheck ok.
Try again to fix race.  distcheck ok.
Another attempt to fix build failures, it seems that hyperref version on autobuilder is too old.  distcheck ok.
BRANCH: created branch barbier
Replace $...$ by \textit{...} to avoid spurious spaces in PDF files
Remove space and ~ before punctuation signs, they are not used in English typography
Fix ~ and ^ in operator list
Remove ellipsis for long commands, sentences are split
MERGE trunk> svn merge --reintegrate https://.../barbier (1976:1980)

Replace $...$ by \textit{...} to avoid spurious spaces in PDF files
Remove space and ~ before punctuation signs, they are not used in English typography
Fix ~ and ^ in operator list
Remove ellipsis for long commands, sentences are split

distcheck ok