diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index af2169c..9643871 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -430,6 +430,7 @@
   misc/seterrno.c \
   stdio/_scprintf.c \
   stdio/_vscprintf.c \
+  stdio/mingw_dummy__lock.c \
   stdio/mingw_lock.c
 
 src_msvcr120_app=\
diff --git a/mingw-w64-crt/crt/crtdll_compat.c b/mingw-w64-crt/crt/crtdll_compat.c
index 3568665..39cc300 100644
--- a/mingw-w64-crt/crt/crtdll_compat.c
+++ b/mingw-w64-crt/crt/crtdll_compat.c
@@ -11,12 +11,6 @@
 #undef __setusermatherr
 void __setusermatherr(__UNUSED_PARAM(int (__cdecl *f)(struct _exception *))) { }
 
-/* Define dummy _lock() and _unlock() functions as crtdll.dll does not provide them */
-void __cdecl _lock(int locknum);
-void __cdecl _unlock(int locknum);
-void __cdecl _lock(__UNUSED_PARAM(int locknum)) { }
-void __cdecl _unlock(__UNUSED_PARAM(int locknum)) { }
-
 /* Define __getmainargs() function via crtdll.dll __GetMainArgs() function */
 extern void __GetMainArgs(int *argc, char ***argv, char ***envp, int expand_wildcards);
 int __cdecl __getmainargs(int *argc, char ***argv, char ***envp, int expand_wildcards, __UNUSED_PARAM(_startupinfo *startup_info))
diff --git a/mingw-w64-crt/stdio/mingw_dummy__lock.c b/mingw-w64-crt/stdio/mingw_dummy__lock.c
new file mode 100644
index 0000000..7afe665
--- /dev/null
+++ b/mingw-w64-crt/stdio/mingw_dummy__lock.c
@@ -0,0 +1,12 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+
+#include <internal.h>
+
+void __cdecl _lock(int locknum);
+void __cdecl _unlock(int locknum);
+void __cdecl _lock(__UNUSED_PARAM(int locknum)) { }
+void __cdecl _unlock(__UNUSED_PARAM(int locknum)) { }