package/libdnet: fix python build

Fix the following build failure raised with python >= 3.11 by
backporting a patch and adding libbsd dependency as suggested by
upstream in https://github.com/ofalk/libdnet/issues/74:

./dnet.c: In function '__Pyx_AddTraceback':
./dnet.c:456:62: error: invalid use of incomplete typedef 'PyFrameObject' {aka 'struct _frame'}
  456 |   #define __Pyx_PyFrame_SetLineNumber(frame, lineno)  (frame)->f_lineno = (lineno)
      |                                                              ^~
./dnet.c:25190:5: note: in expansion of macro '__Pyx_PyFrame_SetLineNumber'
25190 |     __Pyx_PyFrame_SetLineNumber(py_frame, py_line);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/78dff4b514fb7c510f5a745ee6cbbc049ceb2794

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libdnet/0002-Correct-path-to-string-h-from-bsd.patch

@@ -0,0 +1,26 @@
+From 347c23da1ec6f19b0b0143d53edcc209e522bbf2 Mon Sep 17 00:00:00 2001
+From: Oliver Falk <oliver@linux-kernel.at>
+Date: Wed, 29 Jun 2022 13:27:45 +0200
+Subject: [PATCH] Correct path to string.h (from bsd); Fixes #74
+
+[Retrieved (and backported) from:
+https://github.com/ofalk/libdnet/commit/347c23da1ec6f19b0b0143d53edcc209e522bbf2]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ python/dnet.c   | 64 +++++++++++++++++++++++--------------------------
+ python/dnet.pyx |  2 +-
+ 2 files changed, 31 insertions(+), 35 deletions(-)
+
+diff --git a/python/dnet.pyx b/python/dnet.pyx
+index d9cbc90..af65a11 100644
+--- a/python/dnet.pyx
++++ b/python/dnet.pyx
+@@ -40,7 +40,7 @@ cdef extern from *:
+     unsigned long htonl(unsigned long n)
+     unsigned long ntohl(unsigned long n)
+ 
+-cdef extern from "string.h":
++cdef extern from "bsd/string.h":
+     int     strlcpy(char *dst, char *src, int size)
+ 
+ cdef __memcpy(char *dst, object src, int n):

package/libdnet/Config.in

@@ -10,11 +10,22 @@ if BR2_PACKAGE_LIBDNET
 
 config BR2_PACKAGE_LIBDNET_PYTHON
 	bool "libdnet python module"
+	depends on BR2_PACKAGE_LIBBSD_ARCH_SUPPORTS
 	depends on BR2_PACKAGE_PYTHON3
+	depends on !BR2_STATIC_LIBS # libbsd
+	depends on BR2_TOOLCHAIN_HAS_THREADS # libbsd
+	depends on BR2_USE_WCHAR # libbsd
+	select BR2_PACKAGE_LIBBSD
 	help
 	  dnet module for python
 
 comment "dnet module for python requires python3 package"
+	depends on BR2_PACKAGE_LIBBSD_ARCH_SUPPORTS
 	depends on !BR2_PACKAGE_PYTHON3
 
+comment "dnet module for python needs a toolchain w/ dynamic library, threads, wchar"
+	depends on BR2_PACKAGE_LIBBSD_ARCH_SUPPORTS
+	depends on BR2_STATIC_LIBS || !BR2_TOOLCHAIN_HAS_THREADS || \
+		!BR2_USE_WCHAR
+
 endif

package/libdnet/libdnet.mk

@@ -17,7 +17,7 @@ LIBDNET_CONFIG_SCRIPTS = dnet-config
 LIBDNET_DEPENDENCIES = host-pkgconf
 
 ifeq ($(BR2_PACKAGE_LIBDNET_PYTHON),y)
-LIBDNET_DEPENDENCIES += host-python-cython python3
+LIBDNET_DEPENDENCIES += libbsd host-python-cython python3
 LIBDNET_CONF_OPTS += --with-python=$(HOST_DIR)/bin
 LIBDNET_MAKE_ENV += $(PKG_PYTHON_DISTUTILS_ENV)
 LIBDNET_INSTALL_TARGET_OPTS = $(LIBDNET_MAKE_OPTS) DESTDIR=$(TARGET_DIR) INSTALL_STRIP_FLAG=-s install-exec