Make SyntaxCheckers_*_GetLocList() dictionary functions.
Pass a reference to the current checker to syntastic#makeprg#build().
Add an optional 'redirect' argument to CreateAndRegisterChecker().
Change the sh checker to use the new dictionary functions.
Add a new registry method getLocListRaw() (needed for the sh checker).
This patch adds an option 'postprocess' to SyntasticMake(). The value
of this option is a list of names. Each name is translated to a
function syntastic#postprocess#name(). These functions are applied in
order to the list of errors just before SyntasticMake() returns. They
take a single parameter, the list of errors, and are supposed to
returned the processed list.
