wcsmbs: optimize wcsncat

This patch rewrites wcsncat using wcslen, wcsnlen, and wmemcpy.  This is
similar to the optimization done on strncat by 3eb38795db and e80514b5a8.

Checked on x86_64-linux-gnu.

	* wcsmbs/wcsncat.c (wcsncat): Rewrite using wcslen, wcsnlen, and
	wmemcpy.

1 files changed, 3 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 2406275461..d51188cda9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2019-02-27  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+	* wcsmbs/wcsncat.c (wcsncat): Rewrite using wcslen, wcsnlen, and
+	wmemcpy.
+
 	* wcsmbs/wcscpy.c (__wcpcpy): Rewrite using wcslen and wmemcpy.
 
 	* include/wchar.h (__wcscpy): New prototype.