wmake/rules/General/CGAL: lib -> lib64 on 64bit OSs

Patch contributed by Bruno Santos
Resolves patch request http://bugs.openfoam.org/view.php?id=2114

wmake/rules/General/CGAL

@@ -5,8 +5,8 @@ CGAL_INC = \
     -I$(BOOST_ARCH_PATH)/include
 
 CGAL_LIBS = \
-    -L$(MPFR_ARCH_PATH)/lib \
-    -L$(GMP_ARCH_PATH)/lib \
+    -L$(MPFR_ARCH_PATH)/lib$(WM_COMPILER_LIB_ARCH) \
+    -L$(GMP_ARCH_PATH)/lib$(WM_COMPILER_LIB_ARCH) \
     -L$(BOOST_ARCH_PATH)/lib \
     -L$(CGAL_ARCH_PATH)/lib \
     -lCGAL \