[LTP] [PATCH 1/5] Move preadv()/pwritev() backup definitions to LAPI

[Petr Vorel]

Hi Martin,

> Merge existing LAPI definitions of preadv2()/pwritev2() to lapi/uio.h
> and add preadv()/pwritev() definitions from test code. Also fix minor
> bugs in return value type and offset handling.

Good catch int => ssize_t.

Obviously correct, merged with second commit.

Kind regards,
Petr