Comment # 3 on bug 1087135 from Michal Srb

The problem happens when building the bundled llvm:

/home/abuild/rpmbuild/BUILD/rustc-1.24.1-src/src/llvm/include/llvm/ExecutionEngine/Orc/OrcRemoteTargetClient.h:696:26:
error: could not convert
'((llvm::orc::remote::OrcRemoteTargetClient<ChannelT>*)this)->callB<llvm::orc::remote::OrcRemoteTargetRPCAPI::ReadMem>(Src,
Size)' from 'Expected<vector<unsigned char,allocator<unsigned char>>>' to
'Expected<vector<char,allocator<char>>>'
    return callB<ReadMem>(Src, Size);

I am not sure how come the mismatch between vector<char> and vector<unsigned
char> does not cause trouble with gcc 7.

In llvm upstream they changed the char to uint8_t in return value of
`OrcRemoteTargetClient::readMem` in commit
30e9aa60fea44210ac8d843d2f6a4b3bd2578bf4. However, this commit is quite a big
refactoring, so it may not be good idea to take it whole. It may be worth
trying to change just the `OrcRemoteTargetClient::readMem`.