diff -up gmp-5.1.2/tests/cxx/t-ops2.cc.orig gmp-5.1.2/tests/cxx/t-ops2.cc
--- gmp-5.1.2/tests/cxx/t-ops2.cc.orig	2013-05-20 16:59:58.000000000 +0200
+++ gmp-5.1.2/tests/cxx/t-ops2.cc	2013-06-26 22:05:24.510417000 +0200
@@ -26,6 +26,13 @@ the GNU MP Library test suite.  If not,
 #include "gmp-impl.h"
 #include "tests.h"
 
+#ifndef trunc
+double trunc(double x)
+{
+  return x < 0 ? ceil(x) : floor(x);
+}
+#endif
+
 
 #define CHECK1(Type,a,fun) \
   ASSERT_ALWAYS(fun((Type)(a))==fun(a))