Build fails on macports due to "system" path in .pc files

In file included from global/qt_pch.h:58:
In file included from ../../include/QtCore/qglobal.h:1:
In file included from ../../include/QtCore/../../src/corelib/global/qglobal.h:1017:
In file included from ../../include/QtCore/qglobalstatic.h:1:
../../include/QtCore/../../src/corelib/global/qglobalstatic.h:125:45: error: no member named 'load' in 'QBasicAtomicInt'
    bool isDestroyed() const { return guard.load() <= QtGlobalStatic::Destroyed; }
                                      ~~~~~ ^
../../include/QtCore/../../src/corelib/global/qglobalstatic.h:126:40: error: no member named 'load' in 'QBasicAtomicInt'
    bool exists() const { return guard.load() == QtGlobalStatic::Initialized; }
                                 ~~~~~ ^
In file included from global/qt_pch.h:64:
In file included from ../../include/QtCore/qcoreapplication.h:1:
In file included from ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:46:
In file included from /opt/local/include/QtCore/qstring.h:45:
/opt/local/include/QtCore/qchar.h:76:5: error: unknown type name 'QT_ASCII_CAST_WARN_CONSTRUCTOR'
    QT_ASCII_CAST_WARN_CONSTRUCTOR QChar(char c);
    ^
/opt/local/include/QtCore/qchar.h:76:36: error: member 'QChar' has the same name as its class
    QT_ASCII_CAST_WARN_CONSTRUCTOR QChar(char c);
                                   ^
/opt/local/include/QtCore/qchar.h:76:36: error: constructor cannot have a return type
    QT_ASCII_CAST_WARN_CONSTRUCTOR QChar(char c);
                                   ^~~~~
/opt/local/include/QtCore/qchar.h:77:5: error: unknown type name 'QT_ASCII_CAST_WARN_CONSTRUCTOR'
    QT_ASCII_CAST_WARN_CONSTRUCTOR QChar(uchar c);
    ^
/opt/local/include/QtCore/qchar.h:77:36: error: member 'QChar' has the same name as its class
    QT_ASCII_CAST_WARN_CONSTRUCTOR QChar(uchar c);
                                   ^
/opt/local/include/QtCore/qchar.h:77:36: error: constructor cannot have a return type
    QT_ASCII_CAST_WARN_CONSTRUCTOR QChar(uchar c);
                                   ^~~~~
In file included from global/qt_pch.h:64:
In file included from ../../include/QtCore/qcoreapplication.h:1:
In file included from ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:46:
In file included from /opt/local/include/QtCore/qstring.h:46:
/opt/local/include/QtCore/qbytearray.h:207:5: error: unknown type name 'QBool'
    QBool contains(char c) const;
    ^
/opt/local/include/QtCore/qbytearray.h:208:5: error: unknown type name 'QBool'
    QBool contains(const char *a) const;
    ^
/opt/local/include/QtCore/qbytearray.h:209:5: error: unknown type name 'QBool'
    QBool contains(const QByteArray &a) const;
    ^
/opt/local/include/QtCore/qbytearray.h:401:57: error: use of undeclared identifier 'qFree'
inline QByteArray::~QByteArray() { if (!d->ref.deref()) qFree(d); }
                                                        ^
/opt/local/include/QtCore/qbytearray.h:490:28: error: calling a private constructor of class 'QByteRef'
{ Q_ASSERT(i >= 0); return QByteRef(*this, i); }
                           ^
/opt/local/include/QtCore/qbytearray.h:458:12: note: implicitly declared private here
    inline QByteRef(QByteArray &array, int idx)
           ^
/opt/local/include/QtCore/qbytearray.h:492:10: error: calling a private constructor of class 'QByteRef'
{ return QByteRef(*this, i); }
         ^
/opt/local/include/QtCore/qbytearray.h:458:12: note: implicitly declared private here
    inline QByteRef(QByteArray &array, int idx)
           ^
/opt/local/include/QtCore/qbytearray.h:523:8: error: unknown type name 'QBool'
inline QBool QByteArray::contains(const QByteArray &a) const
       ^
/opt/local/include/QtCore/qbytearray.h:524:10: error: use of undeclared identifier 'QBool'
{ return QBool(indexOf(a) != -1); }
         ^
/opt/local/include/QtCore/qbytearray.h:525:8: error: unknown type name 'QBool'
inline QBool QByteArray::contains(char c) const
       ^
/opt/local/include/QtCore/qbytearray.h:526:10: error: use of undeclared identifier 'QBool'
{ return QBool(indexOf(c) != -1); }
         ^
/opt/local/include/QtCore/qbytearray.h:575:8: error: unknown type name 'QBool'
inline QBool QByteArray::contains(const char *c) const
       ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]