COMP: sinclude platform-specific CGAL rules

- permits platform-specific override of the general CGAL rules

wmake/rules/General/CGAL

@@ -14,3 +14,5 @@ CGAL_LIBS = \
     -L$(CGAL_ARCH_PATH)/lib$(WM_COMPILER_LIB_ARCH) \
     -lCGAL \
     -lmpfr
+
+sinclude $(DEFAULT_RULES)/CGAL

wmake/rules/General/general

@@ -27,8 +27,8 @@ endif
 
 include $(DEFAULT_RULES)/general
 include $(DEFAULT_RULES)/$(WM_LINK_LANGUAGE)
--include $(RULES)/general
--include $(RULES)/$(WM_LINK_LANGUAGE)
+sinclude $(RULES)/general
+sinclude $(RULES)/$(WM_LINK_LANGUAGE)
 include $(GENERAL_RULES)/transform