[LibPQ] Bump to 16 and align OpenSSL with HDF5

[jeremiahpslewis]

NOTE: at the moment, super ugly compromise where ./configure old build system is used for apple, new meson build system is used for everything else. As the meson build system was just launched, I expect future releases are likely to be easier to build on apple and we can go back to using one consistent build system (./configure builds don't work on windows).

[jeremiahpslewis]

MinGW build error:

06:35:00] checking for library containing CRYPTO_new_ex_data... no
--
  | [06:35:00] configure: error: library 'eay32' or 'crypto' is required for OpenSSL
  | [06:35:00]  ---> ./configure --prefix=${prefix} --build=${MACHTYPE} --host=${target} --with-includes=${includedir} --with-libraries=${libdir} --without-readline --without-zlib --with-ssl=openssl "${FLAGS[@]}"
  | [06:35:00]  ---> ./configure --prefix=${prefix} --build=${MACHTYPE} --host=${target} --with-includes=${includedir} --with-libraries=${libdir} --without-readline --without-zlib --with-ssl=openssl "${FLAGS[@]}"
  | [06:35:00] Previous command exited with 1
  | [06:35:00] Child Process exited, exit code 1

[jeremiahpslewis]

@giordano I'm out of ideas about how to get Windows to build

[jeremiahpslewis]

@giordano my guess is that using two different build systems for one binary is a significant code smell, but I can't get either build system to build across all targets with OpenSSL 3.

[aviks]

While unfortunate, this looks reasonable to me. Reading the script, it was obvious what is happening, which is good enough, imo.