diff --git a/rostests/winetests/msvcrt/msvcrt.rbuild b/rostests/winetests/msvcrt/msvcrt.rbuild
index 89cd15a3ac2..8f8512a9390 100644
--- a/rostests/winetests/msvcrt/msvcrt.rbuild
+++ b/rostests/winetests/msvcrt/msvcrt.rbuild
@@ -7,6 +7,7 @@
 	<include base="msvcrt">include/reactos/wine/msvcrt</include>
 	<define name="__USE_W32API" />
     <define name="__ROS_LONG64__" />
+	<define name="_CRT_NONSTDC_NO_DEPRECATE" />
 	<library>kernel32</library>
 	<library>msvcrt</library>
 	<file>cpp.c</file>
diff --git a/rostests/winetests/msvcrt/string.c b/rostests/winetests/msvcrt/string.c
index c4b7e078971..a36d3b0ce7f 100644
--- a/rostests/winetests/msvcrt/string.c
+++ b/rostests/winetests/msvcrt/string.c
@@ -28,8 +28,6 @@
 #include <locale.h>
 #include <errno.h>
 
-size_t _mbstrlen(const char*);
-
 static char *buf_to_string(const unsigned char *bin, int len, int nr)
 {
     static char buf[2][1024];