Re: [PATCH] Enable `set -e' in more tests (plus some tweakings).

[Stefano Lattarini]

Tested with:
  1.  Debian GNU/Linux, GNU make 3.79, bash 2.0, gcc 2.95,
      autoconf/autom4te 2.67, in-tree build
  2.  Debian GNU/Linux, GNU make 3.81, bash 4.1.5, gcc 4.4.4,
      autoconf/autom4te 2.63, VAPTHin-tree build
  3.  Debian GNU/Linux, Korn shell 'Version JM 93t+ 2009-05-01',
      FreeBSD make 8.0-1, autoconf/autom4te 2.62, gcc 4.4.4,
      VPATH build
  4.  Debian GNU/Linux, GNU make 3.80, Debian Alquist shell 0.5.5,
      gcc 4.4.4, autoconf/autom4te 2.65, VPATH build
  5.  Debian GNU/Linux, Heirloom sh and make from 2007, gcc 4.4.4,
      autoconf/autom4te 2.63, in tree-build
  6.  Solaris 10, with GNU sed, awk, etc. available, Bash 3.0,
      GNU make 3.81, autoconf/autom4te 2.67, gcc 4.4.4, VPATH build
  7.  Solaris 10, PATH=/usr/bin plus custom directory holding
      programs necessary to the automake testsuite, shell /bin/sh,
      XPG4 make, autoconf/autom4te 2.67, gcc 3.4.3, VPATH build