/usr/lib/x86_64-linux-gnu/pkgconfig/ is in libqt4-dev 4:4.8.7+dfsg-7ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt3Support.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtCLucene.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtCore.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtDBus.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtDeclarative.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtDesigner.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtDesignerComponents.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtGui.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtHelp.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtNetwork.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtScript.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtScriptTools.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtSql.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtSvg.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtTest.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtUiTools.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtXml.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/QtXmlPatterns.pc