* Fix typos:

  - apt-pkg/depcache.cc
* Fix compilation warnings:
  - apt-pkg/acquire.cc
  - apt-pkg/versionmatch.cc
* Compilation fixes and portability improvement for compiling APT against non-GNU libc
  (thanks to Martin Koeppe, closes: #392063):
  - buildlib/apti18n.h.in:
    + textdomain() and bindtextdomain() must not be visible when --disable-nls
  - buildlib/inttypes.h.in: undefine standard int*_t types
  - Append INTLLIBS to SLIBS:
    + cmdline/makefile
    + ftparchive/makefile
    + methods/makefile
* doc/apt.conf.5.xml:
  - clarify whether configuration items of apt.conf are case-sensitive
    (thanks to Vincent McIntyre, closes: #345901)