udevadm: fix option parsing breakage with klibc

The klibc implementation of getopt_long() behaves slightly different
from the glibc one - in particular, it treats the change of the option
string argument between invocations as start of parsing a different
command line, and resets its state.  However, the udevadm code
expected getopt_long() invocations in subcommands to continue parsing
the rest of command line after initial options has been parsed at the
top level; with klibc this broke, causing all udevadm subcommands to
stop recognizing their options.

Instead of relying on the glibc behavior, reset the getopt_long()
state properly before invoking the subcommand handler: move argv to
point to the subcommand name, decrease argc appropriately, and set
optind = 0.  This also fixes a minor bug visible with glibc - without
setting optind = 0 all getopt_long() calls in subcommand handlers were
behaving as if "+" was specified as the first character of the option
string (which disables option reordering), because that state was set
by the first getopt_long() call at the top level, and was not reset
when parsing subcommand options.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>

udev/udevadm.c

@@ -200,7 +200,9 @@ int main(int argc, char *argv[])
 	if (command != NULL)
 		for (i = 0; cmds[i].cmd != NULL; i++) {
 			if (strcmp(cmds[i].name, command) == 0) {
-				optind++;
+				argc -= optind;
+				argv += optind;
+				optind = 0;
 				rc = run_command(udev, &cmds[i], argc, argv);
 				goto out;
 			}