--- a/js/src/jsprvtd.h
+++ b/js/src/jsprvtd.h
@@ -83,22 +83,26 @@
 #define JS_BITS_PER_UINT32_LOG2 5
 #define JS_BITS_PER_UINT32      32
 
 /* Scalar typedefs. */
 typedef uint8  jsbytecode;
 typedef uint8  jssrcnote;
 typedef uint32 jsatomid;
 
+#ifdef __cplusplus
+
 /* Class and struct forward declarations in namespace js. */
 namespace js {
 struct Parser;
 struct Compiler;
 }
 
+#endif
+
 /* Struct typedefs. */
 typedef struct JSArgumentFormatMap  JSArgumentFormatMap;
 typedef struct JSCodeGenerator      JSCodeGenerator;
 typedef struct JSGCThing            JSGCThing;
 typedef struct JSGenerator          JSGenerator;
 typedef struct JSNativeEnumerator   JSNativeEnumerator;
 typedef struct JSFunctionBox        JSFunctionBox;
 typedef struct JSObjectBox          JSObjectBox;