/usr/lib/x86_64-linux-gnu/pkgconfig/ is in libcairo2-dev 1.13.0~20140204-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-svg.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-xcb.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-xlib-xrender.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-pdf.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-fc.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-tee.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-xcb-shm.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-xlib.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-ft.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-ps.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-script.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-png.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/cairo-gobject.pc