Fix compile error with MBED_MEM_TRACING_ENABLED and ARMC6

Author: ccli8

platform/mbed_retarget.cpp

@@ -1339,7 +1339,7 @@ extern "C" void __cxa_guard_abort(int *guard_object_p)
 
 #endif
 
-#if defined(MBED_MEM_TRACING_ENABLED) && (defined(__CC_ARM) || defined(__ICCARM__))
+#if defined(MBED_MEM_TRACING_ENABLED) && (defined(__CC_ARM) || defined(__ICCARM__) || (defined (__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050)))
 
 // If the memory tracing is enabled, the wrappers in mbed_alloc_wrappers.cpp
 // provide the implementation for these. Note: this needs to use the wrappers