- sanitized exit code a bit

Instead of trying a homegrown way to avoid recursive exceptions, let's do it with the defined procedure C++ has for this case: call std::terminate.

This allowed removing some old hackery inherited from Boom and will now hopefully allow sanitizing the exit procedure to the point that it can be done without depending on exit handlers.

src/utility/files_decompress.cpp

@@ -63,7 +63,7 @@ void DecompressorBase::DecompressionError(const char *error, ...) const
 	va_end(argptr);
 
 	if (ErrorCallback != nullptr) ErrorCallback(errortext);
-	else std::terminate();
+	else throw std::runtime_error(errortext);
 }
 
 long DecompressorBase::Tell () const