Add target to binding specification: types #1296
Description
This sub-issue is part of #1232. It concerns adding the types required for specifying the target. The binding specification data types and files should support specifying the target, but functionality (use of this target information) will be implemented in other sub-issues.
We support a fixed set of targets, declared using sum type Target in HsBindgen.Config.ClangArgs, but with an arbitrary environment, using the TargetEnv type.
A binding specification file must specify a target, which must be one of the following:
- A specific target, represented using a target triple string (see
targetTriple) - A special value
any, asserting that the bindings are not target-specific
When generating binding specifications, the specific target must be used.