Fix invalid memory access bug in pager line wrapping

A reference to the first allocated line was cached as the return value.
If calls to add_line would force a reallocation of the view line array
the cached line reference would become invalid and lead to a segfault.
Handle wrapping of the first line of a view
Replace strndup(3) usage with malloc + strncpy

strndup(3) wasn't standardized until POSIX.1-2008, and (more concretely)
isn't available in OS X 10.5 Leopard.

Reported by Samuel Bronson.
Run autoupdate(1) on to get rid of autoconf warnings
Make sure that our .m4 file gets included

That is, make autoconf abort if it's missing.
Tweak Emacs' syntax highlighting of configure.ac
When using autoconf, *all* of our .o files depend on config.h
Add "show-deps" make target; rearrange existing dependencies to match output

The hard-coded dependencies in Makefile were already exactly correct;
they just weren't alphabetized as gcc -MM alphabetizes them.
Use the right Emacs mode for config.make.in
Work around a bug in autoreconf 2.61
Try to automatically re-run configure script when appropriate

But, of course, don't try to run it unless we are actually using it!

[ jf: Update NEWS ]
Read commit IDs from stdin when opened with --stdin

Works for the main and diff view. Examples:

  $ tig --no-walk --stdin < cherry-picks.txt
  $ git rev-list --author=vivien HEAD | tig show --stdin

Requested by Jean-Baptiste Quenot.
[GH #83] WIP: main view lazy navigation mode prototype
Refactor stage view title formatting
Enable lazy navigation mode for the status view
Do not show deleted branch when reloading the branch view

Reported by Vivien.
Fix lazy navigation mode to allow opening the parent tree
Fix status view to show section-level changes in non-lazy navigation mode
[GH #91] Allow to open blob related with added content in a diff
tig-1.1