diff --git a/configure.in b/configure.in
index d6223c4..87dcf06 100644
--- a/configure.in
+++ b/configure.in
@@ -16,7 +16,7 @@
 sysv4*)
 	opsys=svr4
 	;;
-irix5*)
+irix[56]*)
 	opsys=svr4
 	;;
 *)
@@ -126,7 +126,7 @@
 AC_SIG_ATOMIC_T
 AC_CHECK_LIB(nsl, main)
 AC_CHECK_FUNCS(sigaction strerror strsignal pread sys_siglist _sys_siglist getdents mctl putpmsg prctl sendmsg)
-AC_CHECK_HEADERS(sys/filio.h sys/asynch.h sys/stream.h sys/tiuser.h sys/sysconfig.h asm/sigcontext.h ioctls.h sys/ioctl.h sys/ptrace.h termio.h)
+AC_CHECK_HEADERS(sys/filio.h sys/acl.h sys/asynch.h sys/door.h sys/stream.h sys/tiuser.h sys/sysconfig.h asm/sigcontext.h ioctls.h sys/ioctl.h sys/ptrace.h termio.h)
 AC_DECL_SYS_ERRLIST
 AC_DECL_SYS_SIGLIST
 AC_DECL__SYS_SIGLIST