[patch] Chane wfd to static variable in cat.c

[Nan Xiao]

Hi tech@,

It seems "wfd" only need get its value when first calling "raw_cat", so
maybe a static variable should be better. Sorry if I am wrong.

Thanks!

Index: cat.c
===================================================================
RCS file: /cvs/src/bin/cat/cat.c,v
retrieving revision 1.26
diff -u -p -r1.26 cat.c
--- cat.c       19 Oct 2016 18:20:25 -0000      1.26
+++ cat.c       11 Apr 2018 10:05:05 -0000
@@ -223,14 +223,14 @@ raw_args(char **argv)
 void
 raw_cat(int rfd)
 {
-       int wfd;
+       static int wfd;
        ssize_t nr, nw, off;
        static size_t bsize;
        static char *buf = NULL;
        struct stat sbuf;

-       wfd = fileno(stdout);
        if (buf == NULL) {
+               wfd = fileno(stdout);
                if (fstat(wfd, &sbuf))
                        err(1, "stdout");
                bsize = MAXIMUM(sbuf.st_blksize, BUFSIZ);
-- 
Best Regards
Nan Xiao(肖楠)