Upgrading Postgres Client Library to 18_1

[coffeebe4code]

There are still a few outstanding issues, and I'm unsure if some of these values can be set based on the presence of a target feature or glibc version etc.

My steps for doing this was.

1. compile libpq from source with ./configure CC='zig cc' CXX='zig c++' --with-ssl=openssl
2. compare the tag for files needed in the Makefile for each of the 3 folders common port libpq.
3. Update, and remove any files.
4. compile zig version of libpq with zig build -Dssl=OpenSSL
5. read the error output, and start adding new header values and removing the old ones not needed.
6. set values that immediately made sense or set others to null.
7. two issues remain related to size passed to the PG_KEYWORD macro

src/include/parser/kwlist.h:499:40: error: excess elements in array initializer 
PG_KEYWORD("whitespace", WHITESPACE_P, UNRESERVED_KEYWORD, BARE_LABEL)

src/include/parser/kwlist.h:499:60: error: excess elements in array initializer
PG_KEYWORD("whitespace", WHITESPACE_P, UNRESERVED_KEYWORD, BARE_LABEL)

UNRESERVED_KEYWORD and BARE_LABEL
These errors are left in a file provided called compile-errors.txt

I'm no expert at this stuff, and it was fun getting this far. I will need some guidance on some of the new 18_1 header defines, as well as these 2 issues.