C Import convenience

[aep]

importing C code is not a good enough experience.

• c structs are not trackable https://github.com/zetzit/zz/issues/57
• calling c functions is implicitly safe https://github.com/zetzit/zz/issues/2
• c callbacks to c functions are not accepted https://github.com/zx-project/zx/blob/master/modules/curl/src/easy.zz#L30
• using c enums is tedious https://github.com/zx-project/zx/blob/master/modules/curl/src/options.zz#L3

i believe the best course of action is to implement a rough c parser, equivalent in correctness to doxygen, as we only care about consuming the C api (header).

[aep]

this is reasonable now. closing