pgsql: Fix macro problem with gai_strerror on Windows.

Fix macro problem with gai_strerror on Windows.

Commit 5579388d was confused about why gai_strerror() didn't work, and
used gai_strerrorA().  It turns out that we had explicitly undefined
Windows' own macro for that somewhere else.  Get rid of all that, and
use the system headers' definition of gai_sterror() directly as
intended.

Discussion: https://postgr.es/m/CA+hUKGKErNfhmvb_H0UprEmp4LPzGN06yR2_0tYikjzB-2ECMw@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/cce28f62680ca77f18762d58bc31f6b67c6ef692

Modified Files
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src/include/port/win32/netdb.h      | 2 --
src/include/port/win32/sys/socket.h | 7 -------
2 files changed, 9 deletions(-)