libupnpp: fix build with uclibc

Add patch to avoid failing with error if host_os doesn't start with
linux

Fixes:
 - http://autobuild.buildroot.net/results/cfb332a169863bcb3e6bc6ee7d6f6199f856b0b8
 - http://autobuild.buildroot.net/results/2f6f464f6360ed9ea4c238f503d2c3b8ab3cbd86

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libupnpp/0001-Fix-cross-compilation-with-uclibc-on-arm-m68k.patch

@@ -0,0 +1,36 @@
+From 2828c2535d4380419ec5114cc3a0564d3686aba9 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Fri, 4 May 2018 11:45:59 +0200
+Subject: [PATCH] Fix cross-compilation with uclibc on arm/m68k
+
+Commit 3f1132ecd27186fa3f1a87ead6a0389802baccbb breaks cross-compilation
+with uclibc on arm and m68k because host_os is set to
+arm-buildroot-uclinux-uclibc or m68k-buildroot-uclinux-uclibc so add
+uclinux to the linux case
+
+Fixes:
+ - http://autobuild.buildroot.net/results/cfb332a169863bcb3e6bc6ee7d6f6199f856b0b8
+ - http://autobuild.buildroot.net/results/2f6f464f6360ed9ea4c238f503d2c3b8ab3cbd86
+
+[Sent upstream]: https://opensourceprojects.eu/p/libupnpp/code/merge-requests/3
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ configure.ac | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/configure.ac b/configure.ac
+index 8903b72..3bb354c 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -35,7 +35,7 @@ build_linux=no
+ build_mac=no
+ # Detect the target system
+ case "${host_os}" in
+-    linux*) build_linux=yes;;
++    linux*|uclinux*) build_linux=yes;;
+     darwin*) build_mac=yes;;
+     *) AC_MSG_ERROR(["OS $host_os is not supported"]);;
+ esac
+-- 
+2.14.1
+

package/libupnpp/libupnpp.mk

@@ -10,6 +10,8 @@ LIBUPNPP_LICENSE = LGPL-2.1+
 LIBUPNPP_LICENSE_FILES = COPYING
 LIBUPNPP_INSTALL_STAGING = YES
 LIBUPNPP_DEPENDENCIES = expat libcurl libupnp
+# We're patching configure.ac
+LIBUPNPP_AUTORECONF = YES
 
 # configure script fails to link against the dependencies of libupnp
 # and libcurl causing detection to fail when statically linking