Missing includes for uint8_t type in lzlib.h

[Michał Górny]

Hello,

The lzlib.h header installed by lzlib uses the uint8_t type, yet doesn't
include <stdint.h>.  As a result, programs using it fail to compile
unless they happen to include <stdint.h> prior to <lzlib.h>, i.e.:

```
In file included from foo.c:1:
/usr/include/lzlib.h:63:23: error: unknown type name ‘uint8_t’
   63 |                       uint8_t * const buffer, const int size );
      |                       ^~~~~~~
/usr/include/lzlib.h:1:1: note: ‘uint8_t’ is defined in header
‘<stdint.h>’; did you forget to ‘#include <stdint.h>’?
  +++ |+#include <stdint.h>
    1 | /* Lzlib - Compression library for the lzip format
/usr/include/lzlib.h:65:30: error: unknown type name ‘uint8_t’
   65 |                        const uint8_t * const buffer, const int
size );
      |                              ^~~~~~~
/usr/include/lzlib.h:90:25: error: unknown type name ‘uint8_t’
   90 |                         uint8_t * const buffer, const int size
);
      |                         ^~~~~~~
/usr/include/lzlib.h:90:25: note: ‘uint8_t’ is defined in header
‘<stdint.h>’; did you forget to ‘#include <stdint.h>’?
/usr/include/lzlib.h:92:32: error: unknown type name ‘uint8_t’
   92 |                          const uint8_t * const buffer, const int
size );
      |                                ^~~~~~~
```

This was originally reported as build failure in wget2 on Gentoo:
https://bugs.gentoo.org/822057

-- 
Best regards,
Michał Górny