CONFIG: adjust make scripts for darwin

- handling of dead links (find -L -delete unsupported)

- remove ignore case flag on 's/../../i' used in have_scotch script.
  It is unneeded and not tolerated by Darwin's sed.

- avoid embedded comments in EXE_INC (Make/options files), which do
  not work well with the OSX LLVM cpp.
  It strips out the comments but also removes the continuation char.

STYLE: adjust notes about paraview library locations

wmake/scripts/have_scotch

@@ -118,7 +118,7 @@ have_scotch()
     # Ensure consistent sizes between OpenFOAM and scotch header
     # extract 'typedef int64_t SCOTCH_Num' or equivalent
     label=$(sed -ne \
-        's/^.*typedef *\([^ ]*\) *SCOTCH_Num.*/\1/ip' \
+        's/^.*typedef *\([^ ]*\) *SCOTCH_Num.*/\1/p' \
         "$header")
     : ${label:=unknown} # Failsafe value