* add `zig libc` command
* add `--libc` CLI and integrate it with Module and linker code
* implement libc detection and paths resolution
* port LLD ELF linker line construction to stage2
* integrate dynamic linker option into Module and linker code
* implement default link_mode detection and error handling if
user requests static when it cannot be fulfilled
* integrate more linker options
* implement detection of .so.X.Y.Z file extension as a shared object
file. nice try, you can't fool me.
* correct usage text for -dynamic and -static