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/mpi

@@ -3,7 +3,7 @@
 # \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
 #  \\    /   O peration     |
 #   \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-#    \\/     M anipulation  | Copyright (C) 2017 OpenCFD Ltd.
+#    \\/     M anipulation  | Copyright (C) 2017-2018 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
 #     This file is part of OpenFOAM, licensed under GNU General Public License
@@ -11,10 +11,16 @@
 #
 # File
 #     etc/config.sh/mpi
+#     - sourced by OpenFOAM-*/etc/bashrc
 #
 # Description
 #     Setup for MPI communications library for OpenFOAM
-#     Sourced from OpenFOAM-<VERSION>/etc/bashrc
+#
+#     User adjustments are possible in these files:
+#       - config.sh/openmpi-system
+#       - config.sh/openmpi
+#       - config.sh/mpi-user
+#       - config.sh/mpi-system
 #
 #     For USERMPI, the user is responsible for supplying an appropriate
 #     wmake/rules/General/mplibUSERMPI file and managing all settings
@@ -25,31 +31,41 @@ export FOAM_MPI=dummy  # Fallback value
 
 case "$WM_MPLIB" in
 SYSTEMOPENMPI)
-    # Use the system installed openmpi, get library directory via mpicc
+    # The system installed openmpi, locations discovery via mpicc.
     export FOAM_MPI=openmpi-system
 
     # Undefine OPAL_PREFIX if set to one of the paths on foamOldDirs
-    if [ -z "$($foamClean "$OPAL_PREFIX" "$foamOldDirs")" ]
+    if [ -z "$($foamClean -env=OPAL_PREFIX "$foamOldDirs")" ]
     then
         unset OPAL_PREFIX
     fi
+    _foamEtc -config  openmpi-system            # <- Adjustments (optional)
 
-    # Bit of a hack: strip off 'lib' and assume it is the prefix for openmpi
-    # include files and libraries.
-    libDir=$(mpicc --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/')
+    # Respect MPI_ARCH_PATH if set to a valid directory (ie, from user adjustments)
+    if [ -d "$MPI_ARCH_PATH" ]
+    then
+        _foamAddLibAuto $MPI_ARCH_PATH
+    else
+        # Slight hack: strip off 'lib' to get presumed prefix for include and libs
+        libDir=$(mpicc --showme:link | sed -e 's/.*-L\([^ ]*\).*/\1/')
 
-    export MPI_ARCH_PATH="${libDir%/*}"
-    _foamAddLib     $libDir
-    unset libDir
+        export MPI_ARCH_PATH="${libDir%/*}"
+        _foamAddLib  $libDir
+        unset libDir
+    fi
     ;;
 
 OPENMPI)
     export FOAM_MPI=openmpi-1.10.4
-    _foamEtc config.sh/openmpi                  # <- Adjustments (optional)
+    _foamEtc -config  openmpi                   # <- Adjustments (optional)
 
-    export MPI_ARCH_PATH=$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$FOAM_MPI
+    # Respect MPI_ARCH_PATH if set to a valid directory (ie, from user adjustments)
+    if [ ! -d "$MPI_ARCH_PATH" ]
+    then
+        export MPI_ARCH_PATH=$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$FOAM_MPI
+    fi
 
-    # Tell OpenMPI where to find its install directory
+    # Inform openmpi where to find its install directory
     export OPAL_PREFIX=$MPI_ARCH_PATH
 
     if [ "$FOAM_VERBOSE" -a "$PS1" ]
@@ -60,23 +76,23 @@ OPENMPI)
     fi
 
     # Could be sourced from ThirdParty with incomplete environment
-    if command -v _foamAddLib > /dev/null 2>&1  # normal sourcing
+    if command -v _foamAddLibAuto > /dev/null 2>&1  # Normal sourcing
     then
         _foamAddPath    $MPI_ARCH_PATH/bin
-        _foamAddLib     $MPI_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH
         _foamAddMan     $MPI_ARCH_PATH/share/man
+        _foamAddLibAuto $MPI_ARCH_PATH  lib$WM_COMPILER_LIB_ARCH
     fi
     ;;
 
 USERMPI)
     # Use an arbitrary, user-specified mpi implementation
     export FOAM_MPI=mpi-user
-    _foamEtc config.sh/mpi-user                 # <- Adjustments
+    _foamEtc -config  mpi-user                  # <- Adjustments (optional)
     ;;
 
 SYSTEMMPI)
     export FOAM_MPI=mpi-system
-    _foamEtc config.sh/mpi-system               # <- Adjustments (optional)
+    _foamEtc -config  mpi-system                # <- Adjustments (optional)
 
     if [ -z "$MPI_ROOT" ]
     then
@@ -129,11 +145,11 @@ MPICH)
     export MPI_HOME=$MPI_ARCH_PATH
 
     # Could be sourced from ThirdParty with incomplete environment
-    if command -v _foamAddLib > /dev/null 2>&1  # normal sourcing
+    if command -v _foamAddLibAuto > /dev/null 2>&1  # Normal sourcing
     then
         _foamAddPath    $MPI_ARCH_PATH/bin
-        _foamAddLib     $MPI_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH
         _foamAddMan     $MPI_ARCH_PATH/share/man
+        _foamAddLibAuto $MPI_ARCH_PATH  lib$WM_COMPILER_LIB_ARCH
     fi
     ;;