Avoid overflow in memccpy.

Just take the upstream NetBSD code.

Bug: http://code.google.com/p/android/issues/detail?id=43078
Change-Id: Ibbbde9d00e8bc6a09c9503aab2b04b4e3d1f98b0
diff --git a/libc/Android.mk b/libc/Android.mk
index 05373dc..7d66805 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -182,7 +182,6 @@
 	bionic/logd_write.c \
 	bionic/lseek64.c \
 	bionic/md5.c \
-	bionic/memccpy.c \
 	bionic/memchr.c \
 	bionic/memmem.c \
 	bionic/memmove_words.c \
@@ -343,6 +342,7 @@
     upstream-netbsd/libc/stdlib/tdelete.c \
     upstream-netbsd/libc/stdlib/tfind.c \
     upstream-netbsd/libc/stdlib/tsearch.c \
+    upstream-netbsd/libc/string/memccpy.c \
     upstream-netbsd/libc/string/strcasestr.c \
     upstream-netbsd/libc/string/strxfrm.c \
     upstream-netbsd/libc/unistd/killpg.c \