propsal: Add Flag Reference to llgo Build Command Help

[BahaaBBM]

Proposal

Hello Go+ team.

I tried to know the available flags that can be used with the build command in llgo. But it seems I couldn't find any useful resource, it would be very helpful if the help command can also be used to display all the available flags for a commad.

Background

The need of useful information.

Workarounds

none