diff --git a/mozilla/xpcom/typelib/xpidl/xpidl.h b/mozilla/xpcom/typelib/xpidl/xpidl.h
index 915ad765d40..00cf8566615 100644
--- a/mozilla/xpcom/typelib/xpidl/xpidl.h
+++ b/mozilla/xpcom/typelib/xpidl/xpidl.h
@@ -37,6 +37,25 @@
 #include <IDL.h>
 #endif
 
+/*
+ * IDL_tree_warning bombs on libIDL version 6.5, and I don't want to not write
+ * warnings... so I define a versioned one here.  Thanks to Mike Shaver for the
+ * ## idiom, which allows us to pass through varargs calls.
+ */
+#if !(LIBIDL_MAJOR_VERSION == 0 && LIBIDL_MINOR_VERSION == 6 && \
+      LIBIDL_MICRO_VERSION == 5)
+/*
+ * This turns a varargs call to XPIDL_WARNING directly into a varargs call to
+ * IDL_tree_warning.  The only tricky bit is that you must call XPIDL_WARNING
+ * with extra parens, e.g. XPIDL_WARNING((foo, bar, "sil"))
+ *
+ * Probably best removed when we leave 6.5.
+*/
+#define XPIDL_WARNING(x) IDL_tree_warning##x
+#else
+#define XPIDL_WARNING(x) do { } while (0)
+#endif
+
 /*
  * Internal operation flags.
  */
diff --git a/mozilla/xpcom/typelib/xpidl/xpidl_header.c b/mozilla/xpcom/typelib/xpidl/xpidl_header.c
index e5cf0988f01..1a53b1bd068 100644
--- a/mozilla/xpcom/typelib/xpidl/xpidl_header.c
+++ b/mozilla/xpcom/typelib/xpidl/xpidl_header.c
@@ -221,16 +221,12 @@ interface(TreeState *state)
               continue;
 
           case IDLN_CODEFRAG:
-/* IDL_tree_warning crashes in libIDL 0.6.5, sometimes */
-#if !(LIBIDL_MAJOR_VERSION == 0 && LIBIDL_MINOR_VERSION == 6 && \
-      LIBIDL_MICRO_VERSION == 5)
-              IDL_tree_warning(iter, IDL_WARNING1,
-                               "%%{ .. %%} code fragment within interface "
-                               "ignored when generating NS_DECL_IFOO macro; "
-                               "if the code fragment contains method "
-                               "declarations, the macro probably isn't "
-                               "complete.");
-#endif
+              XPIDL_WARNING((iter, IDL_WARNING1,
+                             "%%{ .. %%} code fragment within interface "
+                             "ignored when generating NS_DECL_IFOO macro; "
+                             "if the code fragment contains method "
+                             "declarations, the macro probably isn't "
+                             "complete."));
               continue;
 
           default:
@@ -476,9 +472,9 @@ attr_dcl(TreeState *state)
 static gboolean
 do_enum(TreeState *state)
 {
-    IDL_tree_warning(state->tree, IDL_WARNING1,
-                     "enums not supported, enum \'%s\' ignored",
-                     IDL_IDENT(IDL_TYPE_ENUM(state->tree).ident).str);
+    XPIDL_WARNING((state->tree, IDL_WARNING1,
+                   "enums not supported, enum \'%s\' ignored",
+                   IDL_IDENT(IDL_TYPE_ENUM(state->tree).ident).str));
     return TRUE;
 #if 0
     IDL_tree enumb = state->tree, iter;
@@ -509,9 +505,9 @@ do_const_dcl(TreeState *state)
     if (!IDL_NODE_UP(IDL_NODE_UP(state->tree)) ||
         IDL_NODE_TYPE(IDL_NODE_UP(IDL_NODE_UP(state->tree)))
         != IDLN_INTERFACE) {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "const decl \'%s\' not inside interface, ignored",
-                         name);
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "const decl \'%s\' not inside interface, ignored",
+                       name));
         return TRUE;
     }
 
@@ -530,8 +526,9 @@ do_const_dcl(TreeState *state)
         fprintf(state->file, "\n  enum { %s = %d };\n",
                              name, (int) IDL_INTEGER(dcl->const_exp).value);
     } else {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-            "const decl \'%s\' was not of type short or long, ignored", name);
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "const decl \'%s\' was not of type "
+                       "short or long, ignored", name));
     }
     return TRUE;
 }
@@ -544,8 +541,8 @@ do_typedef(TreeState *state)
         complex;
 
     if (IDL_NODE_TYPE(type) == IDLN_TYPE_SEQUENCE) {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "sequences not supported, ignored");
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "sequences not supported, ignored"));
     } else {
         state->tree = type;
         fputs("typedef ", state->file);
@@ -741,9 +738,9 @@ codefrag(TreeState *state)
 {
     char *desc = IDL_CODEFRAG(state->tree).desc;
     if (strcmp(desc, "C++")) {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "ignoring '%%{%s' escape. "
-                         "(Use '%%{C++' to escape verbatim code.)", desc);
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "ignoring '%%{%s' escape. "
+                       "(Use '%%{C++' to escape verbatim code.)", desc));
 
         return TRUE;
     }
diff --git a/mozilla/xpcom/typelib/xpidl/xpidl_java.c b/mozilla/xpcom/typelib/xpidl/xpidl_java.c
index a925f16bbab..25eb2665039 100644
--- a/mozilla/xpcom/typelib/xpidl/xpidl_java.c
+++ b/mozilla/xpcom/typelib/xpidl/xpidl_java.c
@@ -564,9 +564,9 @@ constant_declaration(TreeState *state)
         IDL_NODE_TYPE(IDL_NODE_UP(IDL_NODE_UP(state->tree))) != 
         IDLN_INTERFACE) {
 
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "A constant \"%s\" was declared outside an interface."
-                         "  It was ignored.", name);
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "A constant \"%s\" was declared outside an interface."
+                       "  It was ignored.", name));
 
         return TRUE;
     }
@@ -614,9 +614,9 @@ constant_declaration(TreeState *state)
 		(isshort ? "short" : "int"),
                 name, (int) IDL_INTEGER(declaration->const_exp).value);
     } else {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "A constant \"%s\" was not of type short or long."
-                         "  It was ignored.", name);	
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "A constant \"%s\" was not of type short or long."
+                       "  It was ignored.", name));	
     }
 
     return TRUE;
@@ -699,9 +699,9 @@ attribute_declaration(TreeState *state)
 static gboolean
 enum_declaration(TreeState *state)
 {
-    IDL_tree_warning(state->tree, IDL_WARNING1,
-                     "enums not supported, enum \'%s\' ignored",
-                     IDL_IDENT(IDL_TYPE_ENUM(state->tree).ident).str);
+    XPIDL_WARNING((state->tree, IDL_WARNING1,
+                   "enums not supported, enum \'%s\' ignored",
+                   IDL_IDENT(IDL_TYPE_ENUM(state->tree).ident).str));
     return TRUE;
 }
 
diff --git a/mozilla/xpcom/typelib/xpidl/xpidl_typelib.c b/mozilla/xpcom/typelib/xpidl/xpidl_typelib.c
index 5d2a1e09071..32657a8e69c 100644
--- a/mozilla/xpcom/typelib/xpidl/xpidl_typelib.c
+++ b/mozilla/xpcom/typelib/xpidl/xpidl_typelib.c
@@ -933,9 +933,9 @@ typelib_const_dcl(TreeState *state)
     if (!IDL_NODE_UP(IDL_NODE_UP(state->tree)) ||
         IDL_NODE_TYPE(IDL_NODE_UP(IDL_NODE_UP(state->tree)))
         != IDLN_INTERFACE) {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "const decl \'%s\' not inside interface, ignored",
-                         name);
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "const decl \'%s\' not inside interface, ignored",
+                       name));
         return TRUE;
     }
 
@@ -987,8 +987,8 @@ typelib_const_dcl(TreeState *state)
         }
         NEXT_CONST(state)++;
     } else {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-            "const decl \'%s\' was not of type short or long, ignored", name);
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+            "const decl \'%s\' was not of type short or long, ignored", name));
     }
     return TRUE;
 
@@ -1000,8 +1000,8 @@ typelib_const_dcl(TreeState *state)
     /* const -> list -> interface */
     if (IDL_NODE_TYPE(IDL_NODE_UP(IDL_NODE_UP(state->tree)))
         != IDLN_INTERFACE) {
-        IDL_tree_warning(state->tree, IDL_WARNING1,
-                         "const decl not inside interface!\n");
+        XPIDL_WARNING((state->tree, IDL_WARNING1,
+                       "const decl not inside interface!\n"));
         return TRUE;
     }
 
@@ -1088,9 +1088,9 @@ typelib_const_dcl(TreeState *state)
 static gboolean
 typelib_enum(TreeState *state)
 {
-    IDL_tree_warning(state->tree, IDL_WARNING1,
-                     "enums not supported, enum \'%s\' ignored",
-                     IDL_IDENT(IDL_TYPE_ENUM(state->tree).ident).str);
+    XPIDL_WARNING((state->tree, IDL_WARNING1,
+                   "enums not supported, enum \'%s\' ignored",
+                   IDL_IDENT(IDL_TYPE_ENUM(state->tree).ident).str));
     return TRUE;
 }