During the exp-run in bug 208158, it was found that biology/ugene gives
errors with libc++ 3.8.0:

In file included from src/QScoreAdapter.cpp:1:
In file included from src/QScoreAdapter.h:4:
In file included from ../../include/U2Core/MAlignment.h:1:
In file included from ../../include/U2Core/../../corelibs/U2Core/src/datatype/MAlignment.h:25:
In file included from ../../include/U2Core/../../corelibs/U2Core/src/datatype/MAlignmentInfo.h:25:
In file included from /usr/local/include/qt5/QtCore/QString:1:
In file included from /usr/local/include/qt5/QtCore/qstring.h:41:
In file included from /usr/local/include/qt5/QtCore/qchar.h:37:
In file included from /usr/local/include/qt5/QtCore/qglobal.h:39:
/usr/include/c++/v1/cstddef:43:15: fatal error: 'stddef.h' file not found
#include_next <stddef.h>

^

This is because the port tries to add /usr/include as a system include
directory, using -isystem, and this screws up the order of include
directories. Fix it by patching up a number of .pri files to avoid
using the -isystem flag.

Approved by: h2+fbsdports@fsfe.org (maintainer)
PR: 209366
MFH: 2016Q2