build: require boost >= 1.71.0

Refs: #5276
Change-Id: Ib62b24b041e21b2c017cd9c290f7d5dc09003d63
diff --git a/tests/wscript b/tests/wscript
index 5a21139..2f12f81 100644
--- a/tests/wscript
+++ b/tests/wscript
@@ -6,5 +6,5 @@
         target=f'{top}/unit-tests',
         name='unit-tests',
         source=bld.path.ant_glob(['*.cpp'] + [f'{tool}/**/*.cpp' for tool in bld.env.BUILD_TOOLS]),
-        use=['core-objects'] + [f'{tool}-objects' for tool in bld.env.BUILD_TOOLS],
+        use=['BOOST_TESTS', 'core-objects'] + [f'{tool}-objects' for tool in bld.env.BUILD_TOOLS],
         install_path=None)