pkgconfig (and gphoto2-config) cflags disagree with installed headers

[tsdgeos]

pkgconfig file says that cflags are

$prefix/include/gphoto2

the headers are installed in

$prefix/include/gphoto2

but then the headers reference eachother with

#include <gphoto2/gphoto2-context.h>

This means that if you only compile using the cflags that pkgconfig tells you to use, compilation fails because file gphoto2/gphoto2-context.h can not be found.

I think the simplest fix is changing pkgconfig (and gphoto2-config) cflags to be $prefix/include/gphoto2 AND $prefix/include/