tests: add iopl.test

* tests/iopl.c: New file.
* tests/iopl.test: New test.
* tests/.gitignore: Add iopl.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add iopl.test.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 047ac60..8be3375 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -119,6 +119,7 @@
 	inet-cmsg \
 	ioctl \
 	ioperm \
+	iopl \
 	ip_mreq \
 	ipc_msg \
 	ipc_msgbuf \
@@ -353,6 +354,7 @@
 	inet-cmsg.test \
 	ioctl.test \
 	ioperm.test \
+	iopl.test \
 	ip_mreq.test \
 	ipc_msg.test \
 	ipc_msgbuf.test \