configure: Add knob to control tirpc support

Allow to disable tirpc from the top level.

Based on patch:
https://github.com/openembedded/openembedded-core/blob/master/meta/recipes-extended/ltp/ltp/0003-Add-knob-to-control-tirpc-support.patch

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
diff --git a/configure.ac b/configure.ac
index da33749..dc0c3d6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -116,6 +116,14 @@
 else
     AC_SUBST([WITH_PYTHON],["no"])
 fi
+
+# TI RPC
+AC_ARG_WITH([tirpc],
+  AC_HELP_STRING([--without-tirpc],
+    [without libtirpc support (default=no)]),
+  [with_tirpc=no],
+  [with_tirpc=yes]
+)
 # END tools knobs
 
 # Testsuites knobs
@@ -189,7 +197,9 @@
 LTP_CHECK_FALLOCATE
 LTP_CHECK_SYSCALL_FCNTL
 LTP_CHECK_SYSCALL_PERF_EVENT_OPEN
+if test "x$with_tirpc" = xyes; then
 LTP_CHECK_TIRPC
+fi
 LTP_CHECK_TEE
 LTP_CHECK_SPLICE
 LTP_CHECK_VMSPLICE