compatible licenses for use with gtk-doc provided build scripts and templates

[Stefan Sauer <ensonic hora-obscura de>]

Hi,

I need some help with https://bugzilla.gnome.org/show_bug.cgi?id=788991

When people setup a new project for gtk-doc one can copy this file
https://git.gnome.org/browse/gtk-doc/tree/examples/Makefile.am

and adjust the settings. The 2 other files in question are copied into
the project when running gtkdocize. One is a makefile snippet and one is
a m4 autotools macro:
https://git.gnome.org/browse/gtk-doc/tree/gtk-doc.m4
https://git.gnome.org/browse/gtk-doc/tree/gtk-doc.make

All files did not had a copyright header so far and where GPL like all
files part of gtk-doc. I added explicit copyright headers in commit
dd6b96534076471689f542b7e8469ec7eff521d3 (not yet released). In commit
d9544728bf823f20c7e724fc764e79a6bc92e13e I added an exception clause,
but I am not sure if 1) this is the right way forward and 2) I need an
okay from everyone who ever touch those files.

Any advice? I am also on #gtkdoc on gimpnet irc.

Stefan