cdefines

Turn #define C codes into Rust constants.

How to use:

Add to code:

```rust extern crate cdefines;

[cdefines::preprocessor]

const IOCTL: &str = "#define TCGETS 0x5401 #define TCSETS 0x5402 #define TCSETSW 0x5403 #define TCSETSF 0x5404"; ```

It gets translated to:

rust const IOCTL_TCGETS: usize = 0x5401; // ... enum IOCTL { TCGETS = 0x5401, // ... }

What is supported

1. Plain integers(hex, oct, bin, dec) e.g. #define A 0x1234.
2. Simple define cascading e.g. #define A 123 and then #define B A.