package/dvdrw-tools: needs host-m4

Fixes
http://autobuild.buildroot.net/results/b2b/b2b836b095251950e3229b66d6ca9faeaec45e72/
http://autobuild.buildroot.net/results/03b/03be24979d3ec4b08ebc7841ce1e2bcb05d26f97/
http://autobuild.buildroot.net/results/083/083ce6e998154a77dbaa16b3bed08570b745e587/
http://autobuild.buildroot.net/results/a51/a51da652314b01ae15f99708c5551f571247342b/



Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>