gphoto2: add upstream commit "Use pthread_t abstract type for thread IDs"

which should fix LLVM 15. ok aja@

graphics/gphoto2/patches/patch-gphoto2_main_c

@@ -0,0 +1,26 @@
+From ccc4c1f092bd21ebc713f4d7b9be85be49f92f1e Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Fri, 2 Sep 2022 12:59:46 -0700
+Subject: [PATCH] gphoto2: Use pthread_t abstract type for thead IDs
+
+Index: gphoto2/main.c
+--- gphoto2/main.c.orig
++++ gphoto2/main.c
+@@ -1198,7 +1198,7 @@ thread_func (void *data)
+ 	pthread_cleanup_pop (1);
+ }
+ 
+-static unsigned int
++static pthread_t
+ start_timeout_func (Camera *camera, unsigned int timeout,
+ 		    CameraTimeoutFunc func, void __unused__ *data)
+ {
+@@ -1219,7 +1219,7 @@ start_timeout_func (Camera *camera, unsigned int timeo
+ }
+ 
+ static void
+-stop_timeout_func (Camera __unused__ *camera, unsigned int id,
++stop_timeout_func (Camera __unused__ *camera, pthread_t id,
+ 		   void __unused__ *data)
+ {
+ 	pthread_t tid = id;