diff --git a/src/qtv.h b/src/qtv.h
index b79885c..c169e86 100644
--- a/src/qtv.h
+++ b/src/qtv.h
@@ -160,7 +160,7 @@ int		qvsnprintf(char *buffer, size_t count, const char *format, va_list argptr);
 
 #if defined(__linux__) || defined(_WIN32) || defined(__CYGWIN__)
 size_t	strlcpy (char *dst, const char *src, size_t siz);
-size_t	strlcat (char *dst, char *src, size_t siz);
+size_t	strlcat (char *dst, const char *src, size_t siz);
 #endif
 
 #ifndef _WIN32
diff --git a/src/sys.c b/src/sys.c
index 9a86116..ca407d5 100644
--- a/src/sys.c
+++ b/src/sys.c
@@ -101,7 +101,7 @@ size_t strlcpy(char *dst, const char *src, size_t siz)
 	return(s - src - 1);	/* count does not include NUL */
 }
 
-size_t strlcat(char *dst, char *src, size_t siz)
+size_t strlcat(char *dst, const char *src, size_t siz)
 {
 	register char *d = dst;
 	register const char *s = src;