Bug#733972: qtbase-opensource-src: Use system's harfbuzz

[Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>]

Source: qtbase-opensource-src
Version: 5.2.0+dfsg-3
Severity: important

Thanks to СhALker:

https://bugreports.qt-project.org/browse/QTBUG-18980
There is a «-system-harfbuzz» configure option.

-- System Information:
Debian Release: jessie/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (500, 'testing'), (101, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.12-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=es_AR.UTF-8, LC_CTYPE=es_AR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash