tests: check decoding of BLK* ioctls

* configure.ac (AC_CHECK_TYPES): Add struct blk_user_trace_setup.
* tests/ioctl_block.c: New file.
* tests/ioctl_block.test: New test.
* tests/.gitignore: Add ioctl_block.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add ioctl_block.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index a3a4abb..cf25ece 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -91,6 +91,7 @@
 getxxid
 inet-cmsg
 ioctl
+ioctl_block
 ioctl_rtc
 ioctl_rtc-v
 ioctl_uffdio