diff --git a/src/lisp.h b/src/lisp.h
index 196a547bd5c..78f12b415bd 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2889,7 +2889,9 @@ extern void xfree P_ ((POINTER_TYPE *));
 
 extern char *xstrdup P_ ((char *));
 
+#ifndef USE_CRT_DLL
 extern char *egetenv P_ ((char *));
+#endif
 
 /* Set up the name of the machine we're running on.  */
 extern void init_system_name P_ ((void));