Update signalDecoder.cpp: Fix OOM crash caused by rtl_433_Decoder_Sta…

…ck to small on Lilygo Lora device (#156)

This fixes the crash caused by OOM when low water mark on rtl_433_Decder_Stack drops below 0.
(See: 1technophile/OpenMQTTGateway#2043)
I increased the memory size by 1500 which after running for a week on 2 different Lilygo Lora ESP32 devices leaves the water mark at just over 1KB -- I want to leave a little spare in case there are other sensor configurations and edge cases that would dip further into the stack.

I also wrapped the definitions of `rtl_433_Decoder_stack` with `ifndef rtl_433_Decoder_Stack` so that users can easily manually tweak the allocated stack size for their own particular situations.

src/signalDecoder.cpp

@@ -27,15 +27,17 @@
 
 /*----------------------------- rtl_433_ESP Internals -----------------------------*/
 
-#if defined(RTL_ANALYZER) || defined(RTL_ANALYZE)
-#  define rtl_433_Decoder_Stack 60000
-#elif defined(RTL_VERBOSE) || defined(RTL_DEBUG)
-#  define rtl_433_Decoder_Stack 30000
-#else
-#  if OOK_MODULATION
-#    define rtl_433_Decoder_Stack 10000
+#ifndef rtl_433_Decoder_Stack
+#  if defined(RTL_ANALYZER) || defined(RTL_ANALYZE)
+#    define rtl_433_Decoder_Stack 60000
+#  elif defined(RTL_VERBOSE) || defined(RTL_DEBUG)
+#    define rtl_433_Decoder_Stack 30000
 #  else
-#    define rtl_433_Decoder_Stack 20000
+#    if OOK_MODULATION
+#      define rtl_433_Decoder_Stack 11500
+#    else
+#      define rtl_433_Decoder_Stack 20000
+#    endif
 #  endif
 #endif
 
@@ -575,4 +577,4 @@ void processSignal(pulse_data_t* rtl_pulses) {
   } else {
     // logprintfLn(LOG_DEBUG, "processSignal() signal placed on rtl_433_Queue");
   }
-}
+}