pkg-perl: fix build of perl XS packages

Set OPTIMIZE in order to avoid the use of the host $Config{optimize} value
which could cause breakage when cross-compiling for the target.

See discussion in http://lists.busybox.net/pipermail/buildroot/2014-August/104129.html

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
perl: bump to version 5.20.0
qemu: bump to version 2.1.0
perl: skip some tests which need the toolchain
perl: fix test IO-Socket-IP
perl: check date in harness
perl-cross: testpack
qemu: add a Config.in.host

after the removal of cpanminus
perl: remove useless modules in target tree

with BR, we never install module from the target
perl-config-tiny: new package
perl-curses: new package
perl-io-socket-ip: new package