pgsql: meson: Fix linking using old OpenSSL lib names

meson: Fix linking using old OpenSSL lib names

Before OpenSSL 1.1.0 the legacy names ssleay32 and libeay32 were
still used on Windows, and while we have support for this auto-
conf the meson buildsystem only used the new names on all plat-
forms. This adds support for the old name scheme when building
on Windows.

This patch only applies to 17 and 16 as master no longer support
OpenSSL 1.0.2.

Author: Darek Ślusarczyk <dslusarczyk(at)splunk(dot)com>
Reviewed-by: Nazir Bilal Yavuz <byavuz81(at)gmail(dot)com>
Reviewed-by: Daniel Gustafsson <daniel(at)yesql(dot)se>
Discussion: https://postgr.es/m/CAN55FZ1Nk8wqY=mTrN78H026TuGV50h2H6uq1PwxhTauPYi3ug@mail.gmail.com
Backpatch-through: 16

Branch
------
REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/60516fc8b491f941988b6f4a3a55167b98a9351b

Modified Files
--------------
meson.build | 33 ++++++++++++++++++++++++++++-----
1 file changed, 28 insertions(+), 5 deletions(-)