tests: add reboot.test

* tests/reboot.c: New file.
* tests/reboot.test: New test.
* tests/.gitignore: Add reboot.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add reboot.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index 9cac19d..88dd092 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -143,6 +143,7 @@
 readlink
 readlinkat
 readv
+reboot
 recvmsg
 rename
 renameat