CONFIG: improve prefix matching for system libraries (#1607)

- missed detection of system libraries when installed with multiarch
  paths like /usr/lib/x86_64-linux-gnu

CONFIG: improve handling of group/user config files (#928)

- changed bashrc handling of FOAM_CONFIG_NOUSER to use
  FOAM_CONFIG_MODE instead. Propagate into foamEtcFile to make this
  a stickier control.

  This change allows better control, but also enables cluster
  installations to define their own value within the OpenFOAM prefs.sh
  file to prevent users accidentally mis-configuring things if
  necessary.

- remove undocumented handling of an (a)ll mode in foamEtcFile to
  avoid potential pitfalls.

- add support for FOAM_CONFIG_ETC handling.
  This allows injection of an extra search layer when finding
  project etc files

ENH: improvements to foamConfigurePaths (#928)

- handle FOAM_CONFIG_ETC implicitly, or explicitly with the new
  -etc option.

STYLE: more explicit wording in foamConfigurePaths usage (#1602)

- document that an absolute path (eg, -scotch-path) overrides/ignores
  the equivalent ThirdParty setting (eg, -scotch)

- longer options -system-compiler and -third-compiler for -system
  and -third, respectively. Clearer as to their purpose.

- adjust the location sanity check to look for META-INFO directory.

bin/tools/lib-dir

@@ -6,11 +6,10 @@
 #   \\  /    A nd           | www.openfoam.com
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
-#     Copyright (C) 2018 OpenCFD Ltd.
+#     Copyright (C) 2018-2020 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
-#     This file is part of OpenFOAM, licensed under GNU General Public License
-#     <http://www.gnu.org/licenses/>.
+#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
 #
 # Script
 #     tools/lib-dir [OPTION] DIR [LIBEXT]
@@ -135,7 +134,7 @@ then
 fi
 
 # 2) Use fallback if the previous failed
-if [ -z "$resolved" -a -n "$alt" ]
+if [ -z "$resolved" ] && [ -n "$alt" ]
 then
     # Fallback
     case "$alt" in