Fix sign-compare warnings in pg_iovec.h.
The code in question (pg_preadv() and pg_pwritev()) has been around
for a while, but commit 15c9ac3629 moved it to a header file. If
third-party code that includes this header file is built with
-Wsign-compare on a system without preadv() or pwritev(), war
Fix sign-compare warnings in pg_iovec.h.
The code in question (pg_preadv() and pg_pwritev()) has been around
for a while, but commit 15c9ac3629 moved it to a header file. If
third-party code that includes this header file is built with
-Wsign-compare on a system without preadv() or pwritev(), war
