[hackers] [sbase] Handle stdin properly in cmp(1) and remove path comparison || FRIGN

[git]

commit c0a2030c14c98f3eb08b8f5ee9ed939383de2296
Author: FRIGN <d...@frign.de>
Date:   Sat Feb 7 21:36:36 2015 +0100

    Handle stdin properly in cmp(1) and remove path comparison
    
    Same paths are undefined behaviour, let's not endorse it.

diff --git a/cmp.c b/cmp.c
index 435048f..b6ff20b 100644
--- a/cmp.c
+++ b/cmp.c
@@ -35,17 +35,17 @@ main(int argc, char *argv[])
        if (argc != 2 || (lflag && sflag))
                usage();
 
-       if (!strcmp(argv[0], argv[1]))
-               return Same;
-
        for (n = 0; n < 2; n++) {
-               if (argv[n][0] == '-' && !argv[n][1])
-                       argv[n] = "/dev/fd/0";
-               fp[n] = fopen(argv[n], "r");
-               if (!fp[n]) {
-                       if (!sflag)
-                               weprintf("fopen %s:", argv[n]);
-                       exit(Error);
+               if (argv[n][0] == '-' && !argv[n][1]) {
+                       argv[n] = "<stdin>";
+                       fp[n] = stdin;
+               } else {
+                       fp[n] = fopen(argv[n], "r");
+                       if (!fp[n]) {
+                               if (!sflag)
+                                       weprintf("fopen %s:", argv[n]);
+                               exit(Error);
+                       }
                }
        }
 
@@ -76,5 +76,10 @@ main(int argc, char *argv[])
                        same = 0;
                }
        }
+
+       for (n = 1; n < 2; n++)
+               if (fp[n] != stdin)
+                       fclose(fp[n]);
+
        return same ? Same : Diff;
 }