Switch to using freetype-config for freetype detection.

This fixes GD compilation against libfreetype 2.5.1 and later after they made
the rather interesting decision to change their include directory layout in a
point release.

The original suggestion in the bug was to use pkg-config, but my inclination is
to use freetype-config instead: we should be able to get the same configuration
information without actually needing pkg-config installed, since pkg-config is
by no means guaranteed to exist on many Unices and distros, whereas
freetype-config should always be present if a libfreetype build environment is
installed. Let's try it out and see what happens.

Fixes bug #64405 (Use freetype-config for determining freetype2 dir(s)).
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Switch to using freetype-config for freetype detection.
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Switch to using freetype-config for freetype detection.
Merge branch 'PHP-5.6'

* PHP-5.6:
  Switch to using freetype-config for freetype detection.
Fixed bug #65486 mysqli_poll() is broken on Win x64

While this issue is visible in mysqli_poll() functions, the cause
lays deeper in the stream to socket casting API. On Win x64 the
SOCKET datatype is a 64 or 32 bit unsigned, while on Linux/Unix-like
it's 32 bit signed integer. The game of casting 32 bit var to/from
64 bit pointer back and forth is the best way to break it.

Further more, while socket and file descriptors are always integers
on Linux, those are different things using different APIs on Windows.
Even though using integer instead of SOCKET might work on Windows, this
issue might need to be revamped more carefully later. By this time
this patch is tested well with phpt and apps and shows no regressions,
neither in mysqli_poll() nor in any other parts.
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fixed bug #65486 mysqli_poll() is broken on Win x64
Merge branch 'PHP-5.6'

* PHP-5.6:
  Fixed bug #65486 mysqli_poll() is broken on Win x64
Merge branch 'master' into str_size_and_int64