ENH: additional handling of questionable bad FOAM_EXT_LIBBIN values

- if FOAM_EXT_LIBBIN is unset and some scripts set this to /usr/lib*
  as a fallback (eg, to avoid an undefined value) this will cause a
  system library to be found before appropriate *_ARCH_PATH entry.

  This was noticed during a scotch compilation without third-party:
  resulting in the system library (/usr/lib64/libscotch.so) to be found
  instead of the SCOTCH_ARCH_PATH location
  (/usr/lib64/mpi/gcc/openmpi/lib64/).

  Simply changing the search order doesn't work for use, since we wish
  to retain a preference for any dynamic libraries discovered in a
  real FOAM_EXT_LIBBIN.

  Circumvent these issues by only taking libraries from
  FOAM_EXT_LIBBIN if it also points to a location within ThirdParty.

wmake/scripts/have_adios2

@@ -79,9 +79,8 @@ have_adios2()
     then
         header=$(findFirstFile $ADIOS2_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $ADIOS2_ARCH_PATH/lib/$library \
             $ADIOS2_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$library \
         )

wmake/scripts/have_boost

@@ -74,9 +74,8 @@ have_boost()
     then
         header=$(findFirstFile $BOOST_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $BOOST_ARCH_PATH/lib/$library \
             $BOOST_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$library \
         )

wmake/scripts/have_ccmio

@@ -80,9 +80,8 @@ have_ccmio()
     then
         header=$(findFirstFile $CCMIO_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $CCMIO_ARCH_PATH/lib/$static \
             $CCMIO_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \
         )

wmake/scripts/have_cgal

@@ -74,9 +74,8 @@ have_cgal()
     then
         header=$(findFirstFile $CGAL_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $CGAL_ARCH_PATH/lib/$library \
             $CGAL_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$library \
         )

wmake/scripts/have_fftw

@@ -75,9 +75,8 @@ have_fftw()
     then
         header=$(findFirstFile $FFTW_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $FFTW_ARCH_PATH/lib/$static \
             $FFTW_ARCH_PATH/lib/$library \
             $FFTW_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \

wmake/scripts/have_hypre

@@ -82,9 +82,8 @@ have_hypre()
     then
         header=$(findFirstFile $HYPRE_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $HYPRE_ARCH_PATH/lib/$library \
             $HYPRE_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$library \
         )

wmake/scripts/have_kahip

@@ -80,9 +80,8 @@ have_kahip()
     then
         header=$(findFirstFile $KAHIP_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $KAHIP_ARCH_PATH/lib/$static \
             $KAHIP_ARCH_PATH/lib/$library \
             $KAHIP_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \

wmake/scripts/have_metis

@@ -81,9 +81,8 @@ have_metis()
     then
         header=$(findFirstFile $METIS_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $METIS_ARCH_PATH/lib/$static \
             $METIS_ARCH_PATH/lib/$library \
             $METIS_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \

wmake/scripts/have_mgridgen

@@ -81,9 +81,8 @@ have_mgridgen()
     then
         header=$(findFirstFile $MGRIDGEN_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $MGRIDGEN_ARCH_PATH/lib/$static \
             $MGRIDGEN_ARCH_PATH/lib/$library \
             $MGRIDGEN_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \

wmake/scripts/have_petsc

@@ -82,9 +82,8 @@ have_petsc()
     then
         header=$(findFirstFile $PETSC_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $PETSC_ARCH_PATH/lib/$library \
             $PETSC_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$library \
         )

wmake/scripts/have_scotch

@@ -81,9 +81,8 @@ have_scotch()
     then
         header=$(findFirstFile $SCOTCH_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $SCOTCH_ARCH_PATH/lib/$static \
             $SCOTCH_ARCH_PATH/lib/$library \
             $SCOTCH_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \

wmake/scripts/have_zoltan

@@ -80,9 +80,8 @@ have_zoltan()
     then
         header=$(findFirstFile $ZOLTAN_ARCH_PATH/include/$header)
 
-        # FOAM_EXT_LIBBIN is allowed to be unset
         library=$(findFirstFile \
-            $FOAM_EXT_LIBBIN/$library \
+            "$(thirdExtLib $library)" \
             $ZOLTAN_ARCH_PATH/lib/$static \
             $ZOLTAN_ARCH_PATH/lib/$library \
             $ZOLTAN_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH/$static \

wmake/scripts/sysFunctions

@@ -21,6 +21,7 @@
 #     isSystem
 #     isAbsdir, hasAbsdir
 #     findFirstFile
+#     thirdExtLib
 #
 # Variables provided
 #     extLiba
@@ -104,6 +105,26 @@ then
         return 2
     }
 
+    # Check for existence of file in FOAM_EXT_LIBBIN,
+    # but not if either file or FOAM_EXT_LIBBIN are empty or
+    # if the FOAM_EXT_LIBBIN is not located in the ThirdParty directory
+    #
+    # On success, echoes the resolved file and returns 0, otherwise returns 2
+    thirdExtLib()
+    {
+        local file="$FOAM_EXT_LIBBIN/$1"
+
+        if  [ -n "$1" ] && \
+            [ -n "$FOAM_EXT_LIBBIN" ] && \
+            [ -n "$WM_THIRD_PARTY_DIR" ] && \
+            [ -f "$file" -a -r "$file" ] && \
+            [ "${FOAM_EXT_LIBBIN#$WM_THIRD_PARTY_DIR}" != "$FOAM_EXT_LIBBIN" ]
+        then
+            echo "$file"
+        else
+            return 2
+        fi
+    }
 fi