Ren'Py module fails to build with recent fribidi

[Maks Verver]

Building in the module directory, e.g. with:

    python2.7 setup.py build -b build-2.7

Fails as follows:

    x86_64-pc-linux-gnu-gcc -pthread -fPIC -DFRIBIDI_ENTRY= -I. -I/usr/include -I/usr/include/SDL -I/usr/include/freetype2 -I/usr/include/python2.7 -c gen/_renpybidi.c -o build-2.7/temp.linux-x86_64-2.7/gen/_renpybidi.o -Wno-unused-function
    In file included from /usr/include/fribidi/fribidi.h:35:0,
                     from gen/_renpybidi.c:235:
    /usr/include/fribidi/fribidi-common.h:65:20: fatal error: glib.h: No such file or directory

This is because the glib headers aren't being included.

Ideally, the sources would include <fribidi.h> (instead of <fribidi/fribidi.h> as they do now) and use `pkg-config --cflags fribidi` to add the required directories to the include path.

A work-around is to export CFLAGS=`pkg-config --cflags fribidi` before running setup.py. But this should probably be done by setup.py script itself.