ENH: improved handling of gmp/mpfr library settings (issue #674)

- export library path for gmp/mpfr from CGAL config files.
  This is required when non-system gmp/mpfr libraries are being
  used, but not using a ThirdParty compiler installation.

- automatically handle lib/ vs lib64/ (eg, for central installations)
  for packages such as boost, CGAL, etc. While the ThirdParty
  compilation of these will normally land in lib64/, this may not be
  the case when they are supplied by another means.

- reworked the handling of foamEtcFile and foamCleanPath for less
  clutter in the configuration files.
  Added the bin/tools/lib-dir script to handle logic that is
  too complex to easily manage in csh.

etc/config.sh/example/compiler

@@ -11,15 +11,15 @@
 #
 # File
 #     config.sh/example/compiler
+#     - sourced by OpenFOAM-*/etc/config.sh/settings
 #
 # Description
 #     Example of fine tuning compiler versions and settings for OpenFOAM
-#     Sourced from OpenFOAM-<VERSION>/etc/config.sh/settings
 #
 #------------------------------------------------------------------------------
 
 # Load the standard versions
-eval $($WM_PROJECT_DIR/bin/foamEtcFile -sh -mode=o config.sh/compiler)
+eval $($WM_PROJECT_DIR/bin/foamEtcFile -mode=o -sh -config compiler)
 
 # Modify/override compiler settings
 case "$WM_COMPILER" in

etc/config.sh/example/openmpi

@@ -11,14 +11,13 @@
 #
 # File
 #     config.sh/example/openmpi
+#     - sourced by OpenFOAM-*/etc/config.sh/mpi
 #
 # Description
 #     Example of fine tuning openmpi settings for OpenFOAM
-#     Sourced from OpenFOAM-<VERSION>/etc/config.sh/settings
 #
 #------------------------------------------------------------------------------
 
-# Modified openmpi settings
 export FOAM_MPI=openmpi-3.0.0
 
 #------------------------------------------------------------------------------

etc/config.sh/example/paraview

@@ -22,7 +22,7 @@
 #
 #------------------------------------------------------------------------------
 
-# Use shipped paraview config file (-mode=o) with a different ParaView_VERSION
+# Use standard paraview config file (-mode=o) with a different ParaView_VERSION
 
 foamFile=$($WM_PROJECT_DIR/bin/foamEtcFile -mode=o config.sh/paraview 2>/dev/null)
 [ $? -eq 0 ] && . $foamFile ParaView_VERSION=5.4.0

etc/config.sh/example/prefs.sh

@@ -11,12 +11,10 @@
 #
 # File
 #     config.sh/example/prefs.sh
+#     - sourced by OpenFOAM-*/etc/bashrc
 #
 # Description
-#     Preset variables for the OpenFOAM configuration - POSIX shell syntax.
-#
-#     The prefs.sh file will be sourced by the OpenFOAM etc/bashrc when it is
-#     found by foamEtcFile.
+#     Example of preset variables for the OpenFOAM configuration (POSIX shell)
 #
 # See also
 #     'foamEtcFile -help' or 'foamEtcFile -list' for information about the
@@ -24,13 +22,8 @@
 #
 #------------------------------------------------------------------------------
 
-#- Compiler location:
-WM_COMPILER_TYPE=ThirdParty
-
-#- Compiler:
+export WM_COMPILER_TYPE=ThirdParty
 export WM_COMPILER=Clang
-
-#- MPI implementation:
 export WM_MPLIB=SYSTEMOPENMPI
 
 #------------------------------------------------------------------------------