Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
497877c3 Add getHardness and getBlastResistance to Material
CraftBukkit Changes:
c4220dc2 Add Unit Tests for geHardness and getBlastResistance
1ac35b6a89