--- a/configure.ac	Fri May 13 15:33:16 2011 +0200
+++ b/configure.ac	Fri May 13 15:34:20 2011 +0200
@@ -365,13 +365,15 @@
 AC_ARG_WITH([rtai-dir],
     AC_HELP_STRING(
         [--with-rtai-dir=<DIR>],
-        [RTAI path (only for RTAI examples)]
+        [RTAI path (only for RTDM Interface or RTAI examples)]
     ),
     [
         rtaidir=[$withval]
+        rtai=1
     ],
     [
         rtaidir=""
+        rtai=0
     ]
 )
 
@@ -387,6 +389,71 @@
 fi
 
 AC_SUBST(RTAI_DIR,[$rtaidir])
+AM_CONDITIONAL(ENABLE_RTAI, test "x$rtai" = "x1")
+AC_SUBST(ENABLE_RTAI,[$rtai])
+
+#------------------------------------------------------------------------------
+# Xenomai path (optional)
+#------------------------------------------------------------------------------
+
+AC_ARG_WITH([xenomai-dir],
+    AC_HELP_STRING(
+        [--with-xenomai-dir=<DIR>],
+        [Xenomai path (only for RTDM Interface)]
+    ),
+    [
+        xenomaidir=[$withval]
+        xeno=1
+    ],
+    [
+        xenomaidir=""
+        xeno=0
+    ]
+)
+
+AC_MSG_CHECKING([for Xenomai path])
+
+if test -z "${xenomaidir}"; then
+    AC_MSG_RESULT([not specified.])
+else
+    if test \! -r ${xenomaidir}/include/xeno_config.h; then
+        AC_MSG_ERROR([no Xenomai installation found in ${xenomaidir}!])
+    fi
+    AC_MSG_RESULT([$xenomaidir])
+fi
+
+AC_SUBST(XENOMAI_DIR,[$xenomaidir])
+AM_CONDITIONAL(ENABLE_XENOMAI, test "x$xeno" = "x1")
+AC_SUBST(ENABLE_XENOMAI,[$xeno])
+
+#------------------------------------------------------------------------------
+# RTDM Interface (optional)
+#------------------------------------------------------------------------------
+
+AC_ARG_ENABLE([rtdm],
+    AC_HELP_STRING(
+        [--enable-rtdm],
+        [Enable RTDM Interface, depends on RTAI or Xenomai]
+    ),
+    [
+        case "${enableval}" in
+            yes) rtdm=1
+                ;;
+            no) rtdm=0
+                ;;
+            *) AC_MSG_ERROR([Invalid value for --enable-rtdm])
+                ;;
+        esac
+    ],
+    [rtdm=0]
+)
+
+if test "x${rtdm}" = "x1"; then
+    AC_DEFINE([EC_RTDM], [1], [RTDM interfaces enabled])
+fi
+AM_CONDITIONAL(ENABLE_RTDM, test "x$rtdm" = "x1")
+AC_SUBST(ENABLE_RTDM,[$rtdm])
+
 
 #------------------------------------------------------------------------------
 # Debug interface
@@ -513,6 +580,31 @@
 fi
 
 #------------------------------------------------------------------------------
+# Use 2 datagrams (payload+last-byte) when sending to mailbox (reduces frame size)
+#------------------------------------------------------------------------------
+
+AC_ARG_ENABLE([mboxframesize],
+    AS_HELP_STRING([--enable-mboxframesize],
+                   [Reduced frame size when sending to mailbox, uses 2 datagrams (default: no)]),
+    [
+        case "${enableval}" in
+            yes) mboxframesize=1
+                ;;
+            no) mboxframesize=0
+                ;;
+            *) AC_MSG_ERROR([Invalid value for --enable-mboxframesize])
+                ;;
+        esac
+    ],
+    [mboxframesize=0]
+)
+
+if test "x${mboxframesize}" = "x1"; then
+    AC_DEFINE([EC_REDUCE_MBOXFRAMESIZE], [1], [Reduced frame size when sending to mailbox])
+fi
+
+
+#------------------------------------------------------------------------------
 # Read alias address from register
 #------------------------------------------------------------------------------
 
@@ -536,6 +628,7 @@
     AC_DEFINE([EC_REGALIAS], [1], [Read alias adresses from register])
 fi
 
+
 #------------------------------------------------------------------------------
 # Command-line tool
 #-----------------------------------------------------------------------------
@@ -626,6 +719,9 @@
         examples/tty/Kbuild
         examples/tty/Makefile
         examples/user/Makefile
+        examples/xenomai/Makefile
+        examples/xenomai_posix/Makefile
+        examples/rtai_rtdm/Makefile
         include/Makefile
         lib/Makefile
         m4/Makefile
@@ -638,6 +734,8 @@
         tool/Makefile
         tty/Kbuild
         tty/Makefile
+        rtdm/Makefile
+        rtdm/Kbuild
 ])
 AC_OUTPUT