diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index b79dc0533..4aecdc3b7 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -50,7 +50,7 @@ endfunction (find_required_library)
 find_package (PkgConfig)
 function (check_library_version VARNAME LIBRARY_WITH_VERSION)
   if (PKG_CONFIG_FOUND)
-    pkg_check_modules (${VARNAME} REQUIRED ${LIBRARY_WITH_VERSION})
+    pkg_check_modules (${VARNAME} ${LIBRARY_WITH_VERSION})
   endif ()
 endfunction ()