THRIFT-874. Disable AX_SIGNED_RIGHT_SHIFT for cross-compiles

When cross-compiling, we cannot run test programs, so
AX_SIGNED_RIGHT_SHIFT won't work.  That macro is only needed for the
runtime library, not the compiler, so we can just skip it if we are
cross-compiling the compiler.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@991256 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/configure.ac b/configure.ac
index bee025f..b5bfcf8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -281,7 +281,9 @@
 AC_CHECK_FUNCS([sched_get_priority_min])
 AC_CHECK_FUNCS([sched_get_priority_max])
 
-AX_SIGNED_RIGHT_SHIFT
+if test "$cross_compiling" = "no" ; then
+  AX_SIGNED_RIGHT_SHIFT
+fi
 
 AX_THRIFT_GEN(cpp, [C++], yes)
 AM_CONDITIONAL([THRIFT_GEN_cpp], [test "$ax_thrift_gen_cpp" = "yes"])