[Feature Request] Specify the arguments type for easy_c in nifs

[jn-jairo]

When using the easy_c the arguments type are automatically set by zigler, but somethings you need a different type.

In my case the argument should be a null terminated string, but it is passing a string without the zero byte at the end, which causes the software to read other things in the memory.

If I write the wrapper function by myself I just need to add the type [*:0]u8 and it works properly, so I believe it should be possible to make an option to pass the argument type for the easy_c in the nifs, so I don't need to write the wrapper by myself just because of an argument type.