+[AM_CONDITIONAL(LINUX25, test x$linux25 = xyes)
+AM_CONDITIONAL(GSS, test x$enable_gss = xyes)
+])
+
+#
+# LB_LINUX_CONFIG_PAG
+#
+AC_DEFUN([LB_LINUX_CONFIG_PAG],
+[AC_MSG_CHECKING([if Linux is patched with basic PAG support])
+LB_LINUX_TRY_COMPILE([#include <linux/sched.h>],[
+unsigned long pag = current->pag;
+],[AC_MSG_RESULT([yes])
+AC_DEFINE(HAVE_LINUX_PAG, 1, [linux has basic PAG support for Lustre])],[
+AC_MSG_RESULT([no])
+])
+])
+
+#
+# LC_LINUX_CONFIG_GSS
+#
+# Build gss and related tools of Lustre. Currently both kernel and user space
+# parts are depend on linux platform.
+#
+AC_DEFUN([LC_LINUX_CONFIG_GSS],
+[AC_MSG_CHECKING([whether to enable gss/krb5 support])
+AC_ARG_ENABLE([gss],
+ AC_HELP_STRING([--enable-gss], [enable gss/krb5 support]),
+ [],[enable_gss='no'])
+AC_MSG_RESULT([$enable_gss])
+
+if test x$enable_gss == xyes; then
+ LB_LINUX_CONFIG_IM([SUNRPC],[],[
+ AC_MSG_ERROR([GSS require that CONFIG_SUNRPC is enabled in your kernel.])
+ ])
+ LB_LINUX_CONFIG_IM([CRYPTO_DES],[],[
+ AC_MSG_WARN([DES support is recommended by using GSS.])
+ ])
+ LB_LINUX_CONFIG_IM([CRYPTO_MD5],[],[
+ AC_MSG_WARN([MD5 support is recommended by using GSS.])
+ ])
+ LB_LINUX_CONFIG_IM([CRYPTO_SHA256],[],[
+ AC_MSG_WARN([SHA256 support is recommended by using GSS.])
+ ])
+ LB_LINUX_CONFIG_IM([CRYPTO_SHA512],[],[
+ AC_MSG_WARN([SHA512 support is recommended by using GSS.])
+ ])
+ LB_LINUX_CONFIG_IM([CRYPTO_ARC4],[],[
+ AC_MSG_WARN([ARC4 support is recommended by using GSS.])
+ ])
+ #
+ # unfortunately AES symbol is depend (optimized) on arch
+ #
+
+ AC_CHECK_LIB(gssapi, gss_init_sec_context, [
+ GSSAPI_LIBS="$GSSAPI_LDFLAGS -lgssapi"
+ ], [
+ AC_MSG_ERROR([libgssapi is not found, consider --disable-gss.])
+ ],
+ )
+
+ AC_SUBST(GSSAPI_LIBS)
+ AC_KERBEROS_V5
+fi