Try hardest of all (last time) to fix redness (r=nthomas).

js/src/imacro_asm.js.in

@@ -157,7 +157,7 @@ function assemble(filename) {
     let igroup = null, imacro = null;
     let opcode2extra = [];
 
-    print("/* GENERATED BY imacro_asm.js FROM " + filename + " -- DO NOT EDIT!!! */");
+    print("/* GENERATED BY imacro_asm.js -- DO NOT EDIT!!! */");
 
     let s = snarf(filename);
     let a = s.split('\n');

js/src/imacros.c.out

@@ -1,4 +1,4 @@
-/* GENERATED BY imacro_asm.js FROM ../imacros.jsasm -- DO NOT EDIT!!! */
+/* GENERATED BY imacro_asm.js -- DO NOT EDIT!!! */
 static struct {
     jsbytecode any_obj[37];
     jsbytecode obj_any[39];