diff --git a/mingw-w64-crt/ssp/memcpy_chk.c b/mingw-w64-crt/ssp/memcpy_chk.c
index 3dee104..8ff41ca 100644
--- a/mingw-w64-crt/ssp/memcpy_chk.c
+++ b/mingw-w64-crt/ssp/memcpy_chk.c
@@ -8,9 +8,9 @@
 
 void __cdecl __chk_fail(void) __attribute__((__noreturn__));
 
-void *__cdecl __memcpy_chk(void *dst, void *src, size_t n, size_t bufsize);
+void *__cdecl __memcpy_chk(void *dst, const void *src, size_t n, size_t bufsize);
 
-void *__cdecl __memcpy_chk(void *dst, void *src, size_t n, size_t bufsize)
+void *__cdecl __memcpy_chk(void *dst, const void *src, size_t n, size_t bufsize)
 {
   if (n > bufsize)
     __chk_fail();
diff --git a/mingw-w64-crt/ssp/memmove_chk.c b/mingw-w64-crt/ssp/memmove_chk.c
index 9d29fef..888c702 100644
--- a/mingw-w64-crt/ssp/memmove_chk.c
+++ b/mingw-w64-crt/ssp/memmove_chk.c
@@ -8,9 +8,9 @@
 
 void __cdecl __chk_fail(void) __attribute__((__noreturn__));
 
-void *__cdecl __memmove_chk(void *dst, void *src, size_t n, size_t bufsize);
+void *__cdecl __memmove_chk(void *dst, const void *src, size_t n, size_t bufsize);
 
-void *__cdecl __memmove_chk(void *dst, void *src, size_t n, size_t bufsize)
+void *__cdecl __memmove_chk(void *dst, const void *src, size_t n, size_t bufsize)
 {
   if (n > bufsize)
     __chk_fail();
diff --git a/mingw-w64-crt/ssp/mempcpy_chk.c b/mingw-w64-crt/ssp/mempcpy_chk.c
index b8fc6db..d04f9a1 100644
--- a/mingw-w64-crt/ssp/mempcpy_chk.c
+++ b/mingw-w64-crt/ssp/mempcpy_chk.c
@@ -9,9 +9,9 @@
 
 void __cdecl __chk_fail(void) __attribute__((__noreturn__));
 
-void *__cdecl __mempcpy_chk(void *dst, void *src, size_t n, size_t bufsize);
+void *__cdecl __mempcpy_chk(void *dst, const void *src, size_t n, size_t bufsize);
 
-void *__cdecl __mempcpy_chk(void *dst, void *src, size_t n, size_t bufsize)
+void *__cdecl __mempcpy_chk(void *dst, const void *src, size_t n, size_t bufsize)
 {
   if (n > bufsize)
     __chk_fail();