Add configure option to enable building unit tests

Same template should be used for other libs...

Change-Id: Icc771cb6b243d215f30fb51c0dbc028e497a74c6
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/vppinfra/configure.ac b/vppinfra/configure.ac
index d0b3a0c..712186a 100644
--- a/vppinfra/configure.ac
+++ b/vppinfra/configure.ac
@@ -31,6 +31,13 @@
 
 ######################################################################
 
+AC_ARG_ENABLE(tests,
+              AC_HELP_STRING([--enable-tests],[Enable unit tests]),
+              [enable_tests=1],
+              [enable_tests=0])
+
+AM_CONDITIONAL(ENABLE_TESTS, test "$enable_tests" = "1")
+
 AC_ARG_WITH(unix,
             AC_HELP_STRING([--with-unix],[Compile unix version of clib]),
 	    [],