tweeper: avoid a reference to $argv in non-cli mode

$argv is not defined in non-cli mode, so protect its usage behind an
is_cli() check.

For instance, this avoids a message in the PHP built-in web server, when
usage() gets called:

  PHP Notice:  Undefined variable: argv in .../tweeper.php on line 357

diff --git a/tweeper.php b/tweeper.php
index f07382b..a9fce9b 100644 (file)
--- a/tweeper.php
+++ b/tweeper.php
@@ -354,7 +354,7 @@ if (is_cli()) {
 }
 
 if (!isset($options['src_url'])) {
-  fwrite($ERROR_STREAM, usage($argv));
+  fwrite($ERROR_STREAM, usage(is_cli() ? $argv : NULL));
   exit(1);
 }