libxml2: add host compile

Several packages may depend on host compiled packages during
the build time (such as the new LTS versions of telephony packages).

This commit adds an option to use the libxml2 to be built as
a host package. Usage would be following:

	PKG_BUILD_DEPENDS:=libxml2/host

Signed-off-by: Jiri Slachta <slachta@cesnet.cz>
znc: link to libstdc++ to fix performance issues on channel join

ZNC uses a map to cache channel memebers on join. Unfortunately uclibc++
uses a naive linked-list implementation with horrible performance, which
can cause joins to take a few minutes on popular channels.

Therefore Switch to libstdc++ which uses a much more performant hashmap.
ZNC by itself is already rather large, so the added footprint of
libstd++ vs uclibc++ does not matter that much anyway.

Should fix #11778.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
dbus host building

Enable dbus host building ( some packages on other feed(s) need dbus on
host side, since packages need to be compiled natively before cross
compiling)
Merge pull request #554 from jslachta/libxml2-host

Signed-off-by: Michael Heimpold <mhei@heimpold.de>
Merge pull request #555 from rpi-openwrt/master

dbus host building