Refactor `LinuxVersion`, ensure user is running on Linux 4.20+
treee2bad7572410844d4d5e4ce7cc41e02589f6270d
drwxr-xr-x - .github
-rw-r--r-- 8 .gitignore
-rw-r--r-- 7501 Cargo.lock
-rw-r--r-- 922 Cargo.toml
-rw-r--r-- 1078 LICENSE
-rw-r--r-- 4525 README.md
-rw-r--r-- 127 build.rs
drwxr-xr-x - cc
drwxr-xr-x - src
drwxr-xr-x - tools