Explain supressed warnings.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@30420 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

build/bakefiles/common.bkl

@@ -379,7 +379,12 @@ $(TAB)copy "$(DOLLAR)(InputPath)" $(SETUPHDIR)\wx\setup.h
         <lib-path>$(LIBDIRNAME)</lib-path>
         <include cond="FORMAT!='autoconf'">$(SETUPHDIR)</include>
         <warnings>max</warnings>
-        <cppflags-watcom>-wcd=549 -wcd=656 -wcd=657 -wcd=667</cppflags-watcom>
+        <cppflags-watcom>
+            -wcd=549 <!-- 'sizeof' operand contains compiler generated information -->
+            -wcd=656 <!-- define this function inside its class definition (may improve code quality) -->
+            -wcd=657 <!-- define this function inside its class definition (could have improved code quality) -->
+            -wcd=667 <!-- 'va_start' macro will not work without an argument before '...' -->
+        </cppflags-watcom>
     </template>
 
     <!-- for both GUI and wxBase libs/samples: -->