Consider use <stdint.h> types or something similar for C output

[uxmal]

In issue #1234, there was a complaint about the C output files Reko generates not being directly compileable. A contributing factor is that Reko is rendering internal PrimitiveType instances directly. These are not recognized by C compilers as valid code.

A possible solution is to have Reko emit types defined in <stdint.h>. Implementing it would result in:

• PrimitiveType.Int32 being rendered as int32_t in C
• PrimitiveType.Int16 rendered as int16_t
• PrimitiveType.UInt64 rendered as uint64_t
  and so on.

However, there are some types that are not defined in <stdint.h>. There is no equivalent to PrimitiveType.Word32, for instance. Granted, uint32_t could be used to render Word32, but this would result in a surjection of multiple Reko PrimitiveTypes mapping onto the same <stdint.h> types. Perhaps Reko should supply a basictypes.h which contains:

typedef unsigned short int word16_t;
typedef unsigned int word32_t;
typedef unsigned long in word64_t;
typedef float float32_t;
typedef float float64_t;

For platforms with 36-bit words, a basictypes32.h should be generated, containing:

typedef int int18_t;
typedef long int int36_t;
// etc

[kimstik]

Or perhaps go further with the C23 feature: _BitInt(N)