Add a check for sg_io_hdr_t and (not tested) check for scsireq_t
presence.

diff --git a/configure.ac b/configure.ac
index 07c0409..3eb89f5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1463,6 +1463,13 @@
 # include <sys/un.h>
 #endif])
 
+dnl Check for scsireq_t and sg_io_hdr_t members
+AC_CHECK_MEMBERS([scsireq_t.cmd, sg_io_hdr_t.interface_id],,,
+[#include <sys/types.h>
+#ifdef HAVE_SCSI_SG_H
+#include <scsi/sg.h>
+#endif])
+
 dnl Check for siginfo_t members
 AC_CHECK_MEMBERS([siginfo_t.si_fd],,,[#include <signal.h>])