Not interested in child exit status

src/conversion.cpp

@@ -48,8 +48,7 @@ void convert(const std::string& path) { // try to convert to ppm using ImageMagi
 
             write_image(std::cout, stdin);
 
-            int exit_status;
-            throw_if_min1(wait(&exit_status));
+            throw_if_min1(wait(nullptr));
             break;
     }
 }