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
CraftBukkit Changes:
17543ecf SPIGOT-5035: Error Using Virtual Merchant GUI
0fc6922b SPIGOT-5028: Villager#setVillagerExperience() doesn't work
bdbdbe44 SPIGOT-5024: Fox error - Unknown target reason
This makes it easier for downstream projects (forks) to replace the
version fetching system with their own. It is as simple as implementing
an interface and overriding the default implementation of
org.bukkit.UnsafeValues#getVersionFetcher()
It also makes it easier for us to organize things like the version
history feature.
Lastly I have updated the paper implementation to check against the site
API rather than against jenkins.
Spottedleaf
Zach Brown
Shane Freeder