编译Rust的项目时候出现了错误：
error: failed to run custom build command for croaring-sys v0.3.7
process didn't exit successfully: /Users/.../grin/target/release/build/croaring-sys-20d6d5c35e3a436a/build-script-build (exit code: 101)
--- stdout
TARGET = Some("x86_64-apple-darwin")
OPT_LEVEL = Some("3")
HOST = Some("x86_64-apple-darwin")
CC_x86_64-apple-darwin = None
CC_x86_64_apple_darwin = None
HOST_CC = None
CC = None
CFLAGS_x86_64-apple-darwin = None
CFLAGS_x86_64_apple_darwin = None
HOST_CFLAGS = None
CFLAGS = None
DEBUG = Some("false")
running: "cc" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-Wall" "-Wextra" "-std=c11" "-march=native" "-O3" "-o" "/Users/.../grin/target/release/build/croaring-sys-4f7af44253f571e8/out/CRoaring/roaring.o" "-c" "CRoaring/roaring.c"
关键的错误信息是：
error: unknown type name 'uint64_t' cargo:warning= uint64_t ri resident_size;
原因是升级了Mac系统之后 C++ .h 不正确造成的。
解决的方式，是删除clang相关的编译环境，并重新安装，首先删除头文件:
rm -rf /usr/local/include/*
再卸载LLVM相关的工具链
brew uninstall llvm
最后需要卸载掉Xcode命令行工具：
rm -rf /Library/Developer/CommandLineTools
卸载掉clang相关工具之后，再重新安装。
安装Xcode命令行工具：
xcode-select --install
安装llvm
brew install --with-toolchain llvm
重新编译正常。
