Corrected autotools.

configure.ac

+#------------------------------------------------------------------------------
+# $Id$
+#------------------------------------------------------------------------------
+
+AC_INIT([ethercat],[1.1],[fp@igh-essen.com])
+AM_INIT_AUTOMAKE([-Wall -Werror foreign dist-bzip2])
+AC_PREFIX_DEFAULT([/opt/etherlab])
+AC_CONFIG_FILES([Makefile master/Makefile devices/Makefile \
+	         examples/mini/Makefile \
+		 examples/rtai/Makefile \
+		 examples/msr/Makefile])
+
+#------------------------------------------------------------------------------
+# Linux sources
+#------------------------------------------------------------------------------
+
+AC_ARG_WITH([linux-dir],
+    AC_HELP_STRING(
+        [--with-linux-dir=<linux-dir>],
+        [Linux source directory @<:@/lib/modules/<kernelversion>/build@:>@]),
+    [ ],
+    [
+	modulesdir=/lib/modules/`uname -r`
+        withval=${modulesdir}/build
+    ])
+
+AC_MSG_CHECKING([for Linux source tree])
+
+if test \! -r ${withval}/Makefile; then
+   echo
+   AC_MSG_ERROR([No Linux kernel tree in $withval])
+fi
+
+AC_SUBST(LINUX_DIR,[$withval])
+AC_SUBST(LINUX_MODULES_DIR,[$modulesdir])
+
+AC_MSG_RESULT($LINUX_DIR)
+
+#------------------------------------------------------------------------------
+
+AC_OUTPUT
+
+#------------------------------------------------------------------------------