llama : integer type consistency in `llama.h`

[jakexcosme]

Note: This issue was copied from ggml-org#4574

Original Author: @MarcusDunn
Original Issue Number: ggml-org#4574
Created: 2023-12-21T19:55:14Z

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Feature Description

llama.h should prefer to use sized (always) + signed (mostly) integers.

Motivation

The integer types in llama.h right now are.

Count	Type
33	int
10	int32_t
24	uint32_t
2	int64_t
2	uint64_t

In ggml-org#4540 there was a discussion around preferences for integer types on new methods.

Avoiding int makes cross platform code simpler at essentially no cost.
Signed makes arithmetic simpler at the cost of some bits if you need something large.

Possible Implementation

1. Change all int's to int32_t
2. As code changes try to prefer signed integers.

We could also do some higher-impact things, but I'd take the lower-impact slower changes over a large find-and-replace.