Use 'ptid_t' instead of 'ptid' for fbsd_next_vfork_done's return type.

'ptid' compiles in C++, but not C.

gdb/ChangeLog:
	* fbsd-nat.c (fbsd_is_vfork_done_pending): Fix return type.

gdb/ChangeLog

@@ -1,3 +1,7 @@
+2016-07-06  John Baldwin  <jhb@FreeBSD.org>
+
+	* fbsd-nat.c (fbsd_is_vfork_done_pending): Fix return type.
+
 2016-07-06  Yao Qi  <yao.qi@linaro.org>
 
 	* arm-tdep.c (arm_vfp_cprc_sub_candidate): Don't call

gdb/fbsd-nat.c

@@ -609,7 +609,7 @@ fbsd_is_vfork_done_pending (pid_t pid)
 /* Check for a pending vfork done event.  If one is found, remove it
    from the list and return the PTID.  */
 
-static ptid
+static ptid_t
 fbsd_next_vfork_done (void)
 {
   struct fbsd_fork_info *info;