Trap on RTX errors if enabled

If MBED_TRAP_ERRORS_ENABLED is defined to 1 then trap on RTX errors.
This includes using mutexes in ISR context.

platform/mbed_retarget.cpp

@@ -1046,3 +1046,67 @@ void operator delete[](void *ptr)
         free(ptr);
     }
 }
+
+#if defined(MBED_CONF_RTOS_PRESENT) && defined(MBED_TRAP_ERRORS_ENABLED) && MBED_TRAP_ERRORS_ENABLED
+
+static const char* error_msg(int32_t status)
+{
+    switch (status) {
+    case osError:
+        return "Unspecified RTOS error";
+    case osErrorTimeout:
+        return "Operation not completed within the timeout period";
+    case osErrorResource:
+        return "Resource not available";
+    case osErrorParameter:
+        return "Parameter error";
+    case osErrorNoMemory:
+        return "System is out of memory";
+    case osErrorISR:
+        return "Not allowed in ISR context";
+    default:
+        return "Unknown";
+    }
+}
+
+extern "C" void EvrRtxKernelError (int32_t status)
+{
+    error("Kernel error %i: %s\r\n", status, error_msg(status));
+}
+
+extern "C" void EvrRtxThreadError (osThreadId_t thread_id, int32_t status)
+{
+    error("Thread %p error %i: %s\r\n", thread_id, status, error_msg(status));
+}
+
+extern "C" void EvrRtxTimerError (osTimerId_t timer_id, int32_t status)
+{
+    error("Timer %p error %i: %s\r\n", timer_id, status, error_msg(status));
+}
+
+extern "C" void EvrRtxEventFlagsError (osEventFlagsId_t ef_id, int32_t status)
+{
+    error("Event %p error %i: %s\r\n", ef_id, status, error_msg(status));
+}
+
+extern "C" void EvrRtxMutexError (osMutexId_t mutex_id, int32_t status)
+{
+    error("Mutex %p error %i: %s\r\n", mutex_id, status, error_msg(status));
+}
+
+extern "C" void EvrRtxSemaphoreError (osSemaphoreId_t semaphore_id, int32_t status)
+{
+    error("Semaphore %p error %i\r\n", semaphore_id, status);
+}
+
+extern "C" void EvrRtxMemoryPoolError (osMemoryPoolId_t mp_id, int32_t status)
+{
+    error("Memory Pool %p error %i\r\n", mp_id, status);
+}
+
+extern "C" void EvrRtxMessageQueueError (osMessageQueueId_t mq_id, int32_t status)
+{
+    error("Message Queue %p error %i\r\n", mq_id, status);
+}
+
+#endif