only include the easylogging++ stack trace code when needed

external/easylogging++/ea_config.h

@@ -2,11 +2,11 @@
 
 #define ELPP_THREAD_SAFE
 #define ELPP_DEFAULT_LOG_FILE ""
-#if !defined __GNUC__ || defined __MINGW32__ || defined __MINGW64__ || defined __ANDROID__
-#else
-#define ELPP_FEATURE_CRASH_LOG 1
-#endif
 #define ELPP_DISABLE_DEFAULT_CRASH_HANDLING
 #define ELPP_NO_CHECK_MACROS
 #define ELPP_WINSOCK2
 #define ELPP_NO_DEBUG_MACROS
+
+#ifdef EASYLOGGING_CC
+#define ELPP_FEATURE_CRASH_LOG
+#endif

src/common/stack_trace.cpp

@@ -28,7 +28,10 @@
 
 #if !defined __GNUC__ || defined __MINGW32__ || defined __MINGW64__ || defined __ANDROID__
 #define USE_UNWIND
+#else
+#define ELPP_FEATURE_CRASH_LOG 1
 #endif
+#include "easylogging++/easylogging++.h"
 
 #include <stdexcept>
 #ifdef USE_UNWIND