wmakeLnInclude -f now also changes the default linking to 'ln -sf'

- this seems to be the most sensible solution.
  The changed time stamps on the links doesn't seem to bother make at all.

src/Allwmake

@@ -5,8 +5,8 @@ set -x
 # update OpenFOAM version strings if required
 wmakePrintBuild -check || /bin/rm -f OpenFOAM/Make/$WM_OPTIONS/global.? 2>/dev/null
 
-wmakeLnInclude -f OpenFOAM -sf
-wmakeLnInclude -f OSspecific/$WM_OS -sf
+wmakeLnInclude -f OpenFOAM
+wmakeLnInclude -f OSspecific/$WM_OS
 Pstream/Allwmake
 
 wmake libo  OSspecific/$WM_OS

src/turbulenceModels/LES/Allwmake

@@ -2,7 +2,7 @@
 cd ${0%/*} || exit 1    # run from this directory
 set -x
 
-wmakeLnInclude -f ../incompressible/LES -sf
+wmakeLnInclude -f ../incompressible/LES
 
 wmake libso LESfilters
 wmake libso LESdeltas