[hackers] [sbase] Prepend "usage: " in usage() || sin

[git]

commit 23fdd768f04feeea72d1ab8c8982585a930687d1
Author:     sin <s...@2f30.org>
AuthorDate: Sun Oct 4 16:58:03 2015 +0100
Commit:     sin <s...@2f30.org>
CommitDate: Sun Oct 4 17:00:47 2015 +0100

    Prepend "usage: " in usage()

diff --git a/getconf.c b/getconf.c
index 7a96a0d..e21f002 100644
--- a/getconf.c
+++ b/getconf.c
@@ -226,7 +226,7 @@ static const struct var limits_l[] = {
 void
 usage(void)
 {
-       eprintf("%s -v spec arc arco\n", argv0);
+       eprintf("usage: %s -v spec arc arco\n", argv0);
 }
 
 int