diff -r f2d5ed0d9686 CMakeLists.txt
--- a/CMakeLists.txt	Tue Dec 01 22:07:24 2015 -0500
+++ b/CMakeLists.txt	Thu Dec 03 20:01:48 2015 +0100
@@ -382,7 +382,7 @@
 
   set(CMAKE_REQUIRED_FLAGS "-Wl,--no-undefined")
   check_c_compiler_flag("" HAVE_NO_UNDEFINED)
-  set(CMAKE_REQUIRED_FLAGS)
+  set(CMAKE_REQUIRED_FLAGS ${ORIG_CMAKE_REQUIRED_FLAGS})
   if(HAVE_NO_UNDEFINED)
     list(APPEND EXTRA_LDFLAGS "-Wl,--no-undefined")
   endif()