vim-syntastic/syntastic ? reverse-engineered prompt

Build me a Vim plugin that checks my files for syntax or lint errors while I edit, using external tools for each file type. I want it to be able to run checks when I save a file or when I ask for them manually, then show the problems in a way that is easy to notice, like the location list, signs in the gutter, and a message when my cursor is on an error line.

It should work across a lot of common languages and config files, and let me choose which checker to use when there are multiple options. If a checker needs extra command line arguments or needs to read config from the project root, make that easy to set per file type. If you need to, look up current Vim plugin docs online to make sure it fits modern Vim setups.