don't avoid emitting part of the allocation bitmap when NOT told to do so

The condition in the if statement is wrong, as what we're trying to achieve
is to avoid emitting the particular piece of allocation bitmap if that piece
is empty AND we specifically request to skip empty bitmaps.

contrib/tmakatos_emitter.cc

@@ -111,7 +111,7 @@ namespace tmakatos_emitter {
 	}
 
 	void binary_emitter::emit_bmp(bool omit_if_zero) {
-		if (!(!bitmap && omit_if_zero))
+		if (bitmap || !omit_if_zero)
 			out_.write((const char*)&bitmap, sizeof bitmap);
 		bitmap = 0;
 		cur++;