Remove progname variable

The error message shouldn't specify the name of the binary, that's
supposed to be known by the caller.

Update test reference outputs.

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

src/link/main.c

@@ -24,8 +24,6 @@ SLONG options = 0;
 SLONG fillchar = 0;
 char *smartlinkstartsymbol;
 
-char *progname;
-
 /*
  * Print the usagescreen
  *
@@ -54,8 +52,6 @@ main(int argc, char *argv[])
 	if (argc == 1)
 		usage();
 
-	progname = "rgblink";
-
 	while ((ch = getopt(argc, argv, "l:m:n:o:O:p:s:tw")) != -1) {
 		switch (ch) {
 		case 'l':