eina_debug: add function to reset debug subsystem after fork

fork() kills this entire subsystem and leaves its internals
in an inactive but allocated state, so it's necessary to explicitly restart
everything in order to guarantee behavior

@feature

Differential Revision: https://phab.enlightenment.org/D6307

src/lib/eina/eina_debug.c

@@ -762,3 +762,14 @@ eina_debug_shutdown(void)
    eina_threads_shutdown();
    return EINA_TRUE;
 }
+
+EAPI void
+eina_debug_fork_reset(void)
+{
+   extern Eina_Bool fork_resetting;
+
+   fork_resetting = EINA_TRUE;
+   eina_debug_shutdown();
+   eina_debug_init();
+   fork_resetting = EINA_FALSE;
+}

src/lib/eina/eina_debug.h

@@ -299,6 +299,13 @@ EAPI Eina_Debug_Timer *eina_debug_timer_add(unsigned int timeout_ms, Eina_Debug_
  */
 EAPI void eina_debug_timer_del(Eina_Debug_Timer *timer);
 
+/**
+ * @brief Reset the eina debug system after forking
+ *
+ * Call this any time the application forks
+ * @since 1.21
+ * */
+EAPI void eina_debug_fork_reset(void);
 /**
  * @}
  */

src/lib/eina/eina_debug_cpu.c

@@ -337,9 +337,12 @@ _eina_debug_cpu_init(void)
 Eina_Bool
 _eina_debug_cpu_shutdown(void)
 {
+   extern Eina_Bool fork_resetting;
+
    if (_eina_debug_sysmon_active)
      eina_lock_take(&_sysmon_lock);
    _eina_debug_cpu_active = 0;
+   if (!fork_resetting)
      eina_condition_wait(&_exit_cond);
    eina_condition_free(&_exit_cond);
    eina_lock_release(&_sysmon_lock);

src/lib/eina/eina_lock.c

@@ -52,9 +52,12 @@ _eina_spinlock_macos_release(Eina_Spinlock *spinlock)
 #endif /* EINA_HAVE_OSX_SPINLOCK */
 
 
+Eina_Bool fork_resetting;
+
 EAPI void
 _eina_lock_debug_abort(int err, const char *fn, const volatile void *ptr)
 {
+   if (fork_resetting) return;
    fprintf(stderr, "EINA ERROR: '%s' on %s %p\n", strerror(err), fn, ptr);
 #ifdef EINA_HAVE_DEBUG_THREADS
    abort();