安装篇：
错误1:
Could not find a package configuration file provided by "LLVM" (requested
version 4.0) with any of the following names
Add the installation prefix of "LLVM" to CMAKE_PREFIX_PATH or set
"LLVM_DIR" to a directory containing one of the above files. If "LLVM"
provides a separate development package or SDK, be sure it has been
installed.
vim ~/.bash_profile
加入配置：
export LLVM_DIR=/usr/local/Cellar/llvm\@4/4.0.1/lib/cmake
保存生效
source ~/.bash_profile
运行安装
rm -rf build/
git submodule update --init --recursive
./eosio_build.sh
再不行请把llvm都删除，重新安装
brew install llvm@4
启动篇：
错误1:
3190000 block_log_exception: Block log exception
Block log was not setup properly with genesis information.
#rm -rf ~/Library/Application\ Support/eosio
错误2:
3020000 fork_database_exception: Fork database exception
fork database is inconsistent with shared memory
./nodeos -e -p eosio --plugin eosio::chain_api_plugin --plugin eosio::history_api_plugin --delete-all-blocks
加上--delete-all-blocks启动参数即可
