cmake: Require CMake 2.8.12 in NC tests

test/nc/CMakeLists.txt

 ## gflags negative compilation tests
 
-cmake_minimum_required (VERSION 2.8)
+cmake_minimum_required (VERSION 2.8.12 FATAL_ERROR)
 
 if (NOT TEST_NAME)
   message (FATAL_ERROR "Missing TEST_NAME CMake flag")
@@ -13,4 +13,4 @@ find_package (gflags REQUIRED)
 include_directories ("${CMAKE_CURRENT_SOURCE_DIR}/..")
 add_definitions (-DTEST_${TEST_NAME_UPPER})
 add_executable (gflags_${TEST_NAME} gflags_nc.cc)
-target_link_libraries(gflags_${TEST_NAME} ${gflags_LIBRARIES})
+target_link_libraries(gflags_${TEST_NAME} gflags)