[patches] string/strncat.c ca'tbe compiled for some archs

[Denis Zaitceff <zaitceff@xxxxxxxxx>]

I have sent this trivial patch to libc-alpha, but they are ignoring it
for 2 months.  Probably it's already ok to send it here?

Since has been changed recently string/strncat.c can't be compiled
anymore for the arch's that have an inline strncat() defined in
bits/string.h.  The reason is that   #undef strncat   is lost.

My case is x86-32 and s390 must be the case too, but I haven't tested it.

2011-09-22  Denis Zaitceff  <zaitceff@xxxxxxxxx>

       * string/strncat.c (strncat): Undef the symbol in case it has been
       defined in bits/string.h.


--- string/strncat.c
+++ string/strncat.c
@@ -25,6 +25,7 @@
 #endif

 #ifndef STRNCAT
+# undef           strncat
 # define STRNCAT  strncat
 #endif