feat: make build_file first non-option argument instead of last one

[guuzaa]

Before nature doesn't support having the build_file in the middle, such as

nature build foo.n -o foo

This PR make it work.

[guuzaa]

By the way, I modified CMakeLists.txt to avoid silent fallback to an older C standard.

[weiwenhao]

I tested the format of commands used by some software, such as the one recommended by docker

Usage: docker stop [OPTIONS] CONTAINER [CONTAINER...]

Nature is expected to follow a similar recommended format

nature subcommand [OPTIONS] entry

In practice, however, the restriction is not strictly limited, and something like the following will work, so the PR will be merged

docker stop 7bc2589420ab -s SIGKILL 2db9c56f3897 7bc2589420ab 2db9c56f3897