get_ppid_of: Add support for DragonFly BSD

[Bruno Haible]

DragonFly BSD has a /proc/<pid>/status file that looks like the FreeBSD one.


2021-06-07  Bruno Haible  <bruno@clisp.org>

        get_ppid_of: Add support for DragonFly BSD.
        * lib/get_ppid_of.c: Treat DragonFly BSD like FreeBSD.

diff --git a/lib/get_ppid_of.c b/lib/get_ppid_of.c
index ed9f25f..f153b75 100644
--- a/lib/get_ppid_of.c
+++ b/lib/get_ppid_of.c
@@ -23,7 +23,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#if defined __linux__ || defined __ANDROID__ || (defined __FreeBSD_kernel__ && 
!defined __FreeBSD__) || defined __GNU__ || defined __FreeBSD__ || defined 
__NetBSD__ || defined __minix || defined __sun /* Linux, GNU/kFreeBSD, 
GNU/Hurd, FreeBSD, NetBSD, Minix, Solaris */
+#if defined __linux__ || defined __ANDROID__ || (defined __FreeBSD_kernel__ && 
!defined __FreeBSD__) || defined __GNU__ || defined __FreeBSD__ || defined 
__DragonFly__ || defined __NetBSD__ || defined __minix || defined __sun /* 
Linux, GNU/kFreeBSD, GNU/Hurd, FreeBSD, NetBSD, Minix, Solaris */
 # include <fcntl.h>
 # include <unistd.h>
 #endif
@@ -108,7 +108,7 @@ get_ppid_of (pid_t pid)
 
 #endif
 
-#if defined __FreeBSD__ || defined __NetBSD__               /* FreeBSD, NetBSD 
*/
+#if defined __FreeBSD__ || defined __DragonFly__ || defined __NetBSD__ /* 
FreeBSD, NetBSD */
 
   /* Read the contents of /proc/<pid>/status into memory.  */
   char filename[6 + 10 + 7 + 1];