Using PGO at compilation

[black7375]

We are already using LTO(Link Time Optimization).
As discussed in #7, we can test popular distributions(doom, spacemacs).

I think optimization will be a little more possible if we profile the distribution when testing the distribution or verifying the execution of the test codes(elisp-benchmark, test).

https://rigtorp.se/notes/pgo/
https://llvm.org/docs/HowToBuildWithPGO.html
https://github.com/facebookincubator/BOLT