Finally declare gnome-common to be GPL 2+, by doing some source code
archaeology.

These files we can effectively ignore:

.gitignore
AUTHORS
ChangeLog.pre-git
NEWS
README
doc-build/README
doc/usage.txt
gnome-common.doap
macros2/README.cvs-commits

The build files you could argue are boilerplate/uncopyrightable:

Makefile.am
autogen.sh
configure.in
doc-build/Makefile.am
macros2/Makefile.am

So that leaves:

doc-build/gnome-doc-common.in
doc-build/omf.make
doc-build/xmldocs.make

Appeared in e16ea58d. Appears to have
been copy-pasted from scrollkeeper-example2, LGPLv2.1.

macros2/gnome-autogen.sh

Can be traced back to gnome-libs 88f7376472d3ee54329213c118b46225703d8223, which
is GPLv2/LGPLv2.

macros2/gnome-code-coverage.m4

LGPLv2.1+.

macros2/gnome-common.m4
macros2/gnome-compiler-flags.m4

Synced with gnome-core as of 425e5cc9, so
LGPLv2.1+.

The long-standing assumption is that gnome-common was GPLv2+, so u...