Fix build with GCC 9

[blechta]

This PR fixes the problem created by #481 with old GCC 9 (for example gcc (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0):

gcc -c -o ../build/ui.o ui/ui.c `pkg-config --cflags gtk+-3.0`
ui/ui.c: In function ‘stopHp’:
ui/ui.c:134:21: error: parameter name omitted
  134 | static void *stopHp(void *) {
      |                     ^~~~~~
ui/ui.c: In function ‘init_running_info’:
ui/ui.c:713:25: error: parameter name omitted
  713 | void* init_running_info(void *){
      |                         ^~~~~~

[blechta]

@lakinduakash I'm not sure whether the patch is correct. Please have it tested with whatever suitable.