tests: disable -Wmissing-field-initializers both for GCC and Clang

tests/CMakeLists.txt

@@ -53,7 +53,7 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
 else()
     set(c_flags ${c_flags} -Wall -Wextra -Werror -Wsign-conversion)
     set(cxx_flags ${cxx_flags} -Wall -Wextra -Werror -Wsign-conversion -fno-rtti -fno-exceptions)
-    if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+    if (CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
         set(c_flags ${c_flags} -Wno-missing-field-initializers)
         set(cxx_flags ${cxx_flags} -Wno-missing-field-initializers)
     endif()