echo(1): check for stdio errors

[Scott Cheloha]

ok?

Index: echo.c
===================================================================
RCS file: /cvs/src/bin/echo/echo.c,v
retrieving revision 1.10
diff -u -p -r1.10 echo.c
--- echo.c      9 Oct 2015 01:37:06 -0000       1.10
+++ echo.c      10 Jul 2022 22:00:18 -0000
@@ -53,12 +53,15 @@ main(int argc, char *argv[])
                nflag = 0;
 
        while (*argv) {
-               (void)fputs(*argv, stdout);
-               if (*++argv)
-                       putchar(' ');
+               if (fputs(*argv, stdout) == EOF)
+                       err(1, "stdout");
+               if (*++argv && putchar(' ') == EOF)
+                       err(1, "stdout");
        }
        if (!nflag)
                putchar('\n');
+       if (fclose(stdout) == EOF)
+               err(1, "stdout");
 
        return 0;
 }