Add macro to define an option for arbitrary args
Add argument options for some syntax checkers

Gnat, GCC, Clang, GFortran and GHC
Document new argument options
Remove redundant import
[Fix #542] Merge branch '542-catch-all-options'

* 542-catch-all-options:
  Remove redundant import
  Document new argument options
  Add argument options for some syntax checkers
  Add macro to define an option for arbitrary args

Conflicts:
	flycheck.el
Update changelog and texinfo manual [#542]

[ci skip]