Enable libc++ bound checks (#6767)

Author: maxtropets

cmake/ccf_app.cmake

@@ -22,6 +22,13 @@ message(STATUS "Compile target platform: ${COMPILE_TARGET}")
 if(USE_LIBCXX)
   list(APPEND COMPILE_LIBCXX -stdlib=libc++)
   list(APPEND LINK_LIBCXX -lc++ -lc++abi -stdlib=libc++)
+
+  if("${CMAKE_BUILD_TYPE}" STREQUAL "Debug")
+    add_compile_options(-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG)
+  elseif("${CMAKE_BUILD_TYPE}" STREQUAL "Release")
+    add_compile_options(-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST)
+  endif()
+
 endif()
 
 # Enclave library wrapper