commandline parsing: Fix the macfreetv crash

Basically, somewhat of a "duh" now that we have optional_arguments on OSX.
It is highly annoying however that getopt_long behaviour differs so much
between gnu and BSD implementations, and then is even BUGGY on darwin.
'--option=value' is uniformly supported  and '--option value' is a GNU getopt thing.

imperfect world etc...
(cherry picked from commit 687c8659)

src/config/cmdline.c

@@ -283,6 +283,14 @@ int __config_LoadCmdLine( vlc_object_t *p_this, int *pi_argc,
                     psz_name = p_conf->psz_name;
                 }
 
+               if( p_conf->i_type != CONFIG_ITEM_BOOL && !optarg )
+               {
+                   fprintf( stderr, "Warning: missing argument for option --%s\n", p_conf->psz_name );
+                   fprintf( stderr, "Try specifying options as '--optionname=value' instead of '--optionname value'\n" );
+                   continue;
+               }
+
+
                 switch( p_conf->i_type )
                 {
                     case CONFIG_ITEM_STRING: