icu4c: Update to 51.1
gcc47: minor update to 4.7.3

Tested buildability on x86_64-linux + stdenv-updates.
linux-3.2: upgrade to 3.2.43
vlc: upgrade to 2.0.6
boost-1.44.0: also apply time utc patch that was applied for 1.49.0. Needed to be adapted for 1.44.0.