[rtems-libbsd commit] libbsd.txt: Move system control hints

[Sebastian Huber]

Module:    rtems-libbsd
Branch:    6-freebsd-12
Commit:    bb925469870874289aa88a2ef03d98a79b91dbdf
Changeset: http://git.rtems.org/rtems-libbsd/commit/?id=bb925469870874289aa88a2ef03d98a79b91dbdf

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Mon May 23 16:09:29 2022 +0200

libbsd.txt: Move system control hints

Generalize hint.

---

 CONTRIBUTING.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 316a851a..796eafc9 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -669,3 +669,10 @@ Here you see that the SYSINIT(9) entries are no longer static.  The
 ``*_REFERENCE()`` macros will create references to the corresponding modules
 which are later resolved by the linker.  The application has to provide an
 object file with references to all required FreeBSD modules.
+
+System Control Hints
+====================
+
+If you get undefined references to ``_bsd_sysctl_*`` symbols, then you have to
+locate and add the associated system control node, see
+`SYSCTL(9) <http://www.freebsd.org/cgi/man.cgi?query=SYSCTL_DECL&sektion=9>`_.