[hackers] [sbase] Don't close stdin early in sed(1) || sin

[git]

commit ea819714c22e5a7feed13107b6e1662b3a6412cd
Author: sin <s...@2f30.org>
Date:   Thu Apr 9 15:31:41 2015 +0100

    Don't close stdin early in sed(1)
    
    Fix by emg.

diff --git a/sed.c b/sed.c
index ec8c290..6b10eb6 100644
--- a/sed.c
+++ b/sed.c
@@ -1105,7 +1105,7 @@ next_file(void)
 
        if (file == stdin)
                clearerr(file);
-       if (file)
+       else if (file)
                fshut(file, "<file>");
        file = NULL;