pwdx: write errors to stderr

Includes also magic number removal (return value 1 to EXIT_FAILURE),
and proper null assignment to end of string.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

pwdx.c

@@ -98,7 +98,9 @@ int main(int argc, char *argv[])
 
 		if (len < 0) {
 			s = strerror(errno == ENOENT ? ESRCH : errno);
-			retval = 1;
+			retval = EXIT_FAILURE;
+			fprintf(stderr, "%s: %s\n", argv[i], s);
+			continue;
 		} else {
 			pathbuf[len] = 0;
 			s = pathbuf;