More minor bugfixes

- make pollcat_loop() work as expected with no structs linked, by
  - calling usleep() instead of poll()
  - refactoring delay calculation and reset into pollcat_time_value()
- simplify pollcat_timer_dispatch() in case of slow callbacks
  - deprecate pollcat_timer_dispatch_thresh
- revise tests/timer.c to support two new options:
  - -s to monitor stdin with pollcat_fd_add()
  - -w to use pollcat_loop() instead of handling main-loop separately
- make pollcat_dump() always present in header, since it's always compiled in
- add Makefile rules for installing tests, for easier running on cross-compiled targets

include/pollcat/pollcat.h

@@ -1,7 +1,7 @@
 /** Wrapper structure for poll()
  *
  *  This file is part of the Pollcat Library.
- *  Copyright (C) 2022 Expatria Technologies Inc.
+ *  Copyright (C) 2022,2025 Expatria Technologies Inc.
  *  Contact: Morgan Hughes <morgan@expatria.ca>
  *
  *  The Pollcat Library is free software: you can redistribute it and/or modify it under
@@ -40,9 +40,7 @@
 
 #include <stdlib.h>
 #include <poll.h>
-#if POLLCAT_DEBUG
 #include <stdio.h>
-#endif
 
 
 /** Optional function to call on fatal error; if unset an assert()-style message will be
@@ -123,11 +121,9 @@ void pollcat_time_reduce (int time);
 int pollcat_poll (void);
 
 
-#if POLLCAT_DEBUG
-/** Prints the pollfd array to a given file handle
+/** Prints the pollfd array to a given file handle, if POLLCAT_DEBUG is nonzero
  */
 void pollcat_dump (FILE *fp);
-#endif
 
 
 #endif /* _INCLUDE_POLLCAT_POLLCAT_H_ */

include/pollcat/timer.h

@@ -28,8 +28,9 @@
 typedef uint64_t pollcat_time_t;
 
 
-/** Grace period in milliseconds for late timers, set to 0 for exact match */
-extern pollcat_time_t  pollcat_timer_dispatch_thresh;
+/** This was removed and replaced with a simpler implementation which allowed slow/late
+ *  timers to run reliably.  Setting it now has no effect. */
+extern pollcat_time_t  pollcat_timer_dispatch_thresh __attribute__((deprecated));
 
 
 /** Maximum number of times to run the dispatch loop, set to -1 for no limit */