+   <https://www.gnu.org/licenses/>.  */
 
 #include <string.h>
 
-#ifdef _LIBC
-# include <memcopy.h>
-#endif
-
 #ifndef STRNCAT
 # undef strncat
 # define STRNCAT  strncat
@@ -29,54 +25,16 @@
 char *
 STRNCAT (char *s1, const char *s2, size_t n)
 {
-  char c;
   char *s = s1;
 
   /* Find the end of S1.  */
-  do
-    c = *s1++;
-  while (c != '\0');
-