一直报这个错误，找了很久才找到问题。 google也查不到！因此记录一下踩过的坑。

/usr/bin/ld: cannot find /usr/local/lib/clang/5.0.0/lib/linux/libclang_rt.profile-i386.a: No such file or directory
clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation)

-fprofile-instr-generate