PVS-Studio warning V640 for xpdfwin

static void actlist_splay(actlist_t*a, point_t p1, point_t p2)
{

  ....
  while(1)
  {
    ....
    if(!a->root->rightchild)
      c = 1;break;
    ....
  }
}

This suspicious code was found in xpdfwin project by PVS-Studio static code analyzer.
Warning message is:
V640 Consider inspecting the application's logic. It is possible that several statements should be braced. active.c 423

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/