fix: forks should exit

src/midi.c

@@ -1,6 +1,5 @@
-#include <GLFW/glfw3.h>
 #include <alsa/asoundlib.h>
-#include <bsd/string.h>
+#include <stdlib.h>
 
 #include "types.h"
 
@@ -61,5 +60,5 @@ bool midi_background_listen(const MidiDevice *device,
 
   log_info("(%s) background acquisition stopped by main thread (pid: %d)",
            device->name, pid);
-  return false;
+  exit(EXIT_SUCCESS);
 }

src/state.c

@@ -1,5 +1,6 @@
 #include <log.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "types.h"
 
@@ -619,7 +620,7 @@ bool state_background_write(SharedContext *context,
   }
 
   log_info("(state) background writing stopped by main thread (pid: %d)", pid);
-  return false;
+  exit(EXIT_SUCCESS);
 }
 
 void state_init(SharedContext *context, const StateConfig *state_config,