OK, final fix not to impute JS_ARGUMENT_FORMATTER_DEFINED from va_start (duh).

Despite my stupidity here, I must say that over-includers elsewhere of both
jspubtd.h and jsapi.h, and even jscntxt.h, with system headers intermixed, suck
a lot too.

js/src/jsapi.h

@@ -192,10 +192,11 @@ JS_PushArgumentsVA(JSContext *cx, void **markp, const char *format, va_list ap);
 extern JS_PUBLIC_API(void)
 JS_PopArguments(JSContext *cx, void *mark);
 
-#ifdef va_start
+#ifdef JS_ARGUMENT_FORMATTER_DEFINED
+
 /*
  * Add and remove a format string handler for JS_{Convert,Push}Arguments{,VA}.
- * The handler function has this signature:
+ * The handler function has this signature (see jspubtd.h):
  *
  *   JSBool MyArgumentFormatter(JSContext *cx, const char *format,
  *                              JSBool fromJS, jsval **vpp, va_list *app);
@@ -232,27 +233,14 @@ JS_PopArguments(JSContext *cx, void *mark);
  * is typically a string constant.  If format is in dynamic storage, it is up
  * to the caller to keep the string alive until Remove is called.
  */
-
-#ifndef JS_ARGUMENT_FORMATTER_DEFINED
-#define JS_ARGUMENT_FORMATTER_DEFINED 1
-/* XXX typedef'd here and in jspubtd.h #ifdef va_start, even though we include
- * XXX jspubtd.h up above, to avoid bad XXX includers who grab jspubtd.h, then
- * XXX <stdarg.h>, then jsapi.h, thereby hiding the jspubtd def but unhiding
- * XXX the typedef use below in JS_AddArgumentFormatter; we need jspubtd.h to
- * XXX do the typedef for jsapi.h-independent files such as jscntxt.h.
- */
-typedef JSBool
-(* CRT_CALL JSArgumentFormatter)(JSContext *cx, const char *format,
-				 JSBool fromJS, jsval **vpp, va_list *app);
-#endif
-
 JS_PUBLIC_API(JSBool)
 JS_AddArgumentFormatter(JSContext *cx, const char *format,
 			JSArgumentFormatter formatter);
 
 JS_PUBLIC_API(void)
 JS_RemoveArgumentFormatter(JSContext *cx, const char *format);
-#endif /* va_start */
+
+#endif /* JS_ARGUMENT_FORMATTER_DEFINED */
 
 extern JS_PUBLIC_API(JSBool)
 JS_ConvertValue(JSContext *cx, jsval v, JSType type, jsval *vp);

js/src/jspubtd.h

@@ -239,14 +239,12 @@ typedef const JSErrorFormatString *
 			     const uintN errorNumber);
 
 #ifdef va_start
-#ifndef JS_ARGUMENT_FORMATTER_DEFINED
 #define JS_ARGUMENT_FORMATTER_DEFINED 1
-/* XXX typedef'd here and in jsapi.h, see XXX comment there. */
+
 typedef JSBool
 (* CRT_CALL JSArgumentFormatter)(JSContext *cx, const char *format,
 				 JSBool fromJS, jsval **vpp, va_list *app);
 #endif
-#endif
 
 JS_END_EXTERN_C