* PHP-7.3:
  Update NEWS
  Fix bug #79037 (global buffer-overflow in `mbfl_filt_conv_big5_wchar`)
  Fix #79099: OOB read in php_strip_tags_ex
  Fix #79091: heap use-after-free in session_create_id()

Due to ASLR restrictions, preloading on Windows does not work with
any code that has preloading dependencies on internal classes.
This effectively makes it unusable for any non-trivial codebase.

Instead of pretending like preloading is going to work, only to
make people realize that it really doesn't once they get beyond
a dummy example, we disable support for preloading on Windows
entirely.

Closes GH-4999.

Previously this generated a notice, but would likely generate an
Error when unserializing.

Now we treat it with the same distinction as direct property
accesses, i.e. referencing an unset/undefined normal property
stays a notice, while a typed property becomes an Error exception.

This fixed bug #79002.

Closes GH-5050.

* PHP-7.3:
  Fix #54298: Using empty additional_headers adding extraneous CRLF

If the header string is empty, we pass `NULL` to `php_mail()` to avoid
further checks on the string length.

OpenSSL 1.1 does not need crypto locking callbacks, so avoid
detecting and linking against it in the first place.

* PHP-7.3:
  Fix #79068: gdTransformAffineCopy() changes interpolation method

We port
<https://github.com/libgd/libgd/commit/9088591eae437358ee5b929adf82865e37e3001e>.

Only set HAVE_CURL_OPENSSL flag, and remove Windows specific code,
as all of this is only relevant for OpenSSL < 1.1, which is not
used on Windows.