[gimp] icons: add COPYING files for icon themes.

[Jehan <jehanp src gnome org>]

commit 5e7bcc291bd5575ce89801e83539f2bca2924048
Author: Jehan <jehan girinstud io>
Date:   Wed Feb 9 16:14:44 2022 +0100

    icons: add COPYING files for icon themes.
    
    Our Symbolic icon theme comes from the art-libre theme now archived by
    the GNOME design team. It had various authors, including originally
    Jakub Steiner and Barbara Muraus, then jEsuSdA, Klaus Staedtler,
    Alexandre Prokoudine and Aryeom Han. Various other people tweaked the
    icons and may have contributed. See the git log for details.
    
    The Color icon theme is more of an original work by Klaus Staedtler, as
    I understand it, with some additional icons by Alexandre Prokoudine,
    Aryeom Han and other contributors. See the git log for details.
    
    This makes licensing clearer for these specific subsets of the project.

 LICENSE                |  2 ++
 icons/Color/COPYING    | 10 ++++++++++
 icons/Symbolic/COPYING | 16 ++++++++++++++++
 3 files changed, 28 insertions(+)
---
diff --git a/LICENSE b/LICENSE
index 79828fcd18..135927746d 100644
--- a/LICENSE
+++ b/LICENSE
@@ -25,3 +25,5 @@
   GNU LESSER GENERAL PUBLIC LICENSE -- see the 'COPYING' file in the
   libgimp directory for details.
 
+* Icon themes are licensed under Creative Commons by-sa 3.0 or 4.0. See
+  the 'COPYING' files in icons/Symbolic and icons/Color respectively.
diff --git a/icons/Color/COPYING b/icons/Color/COPYING
new file mode 100644
index 0000000000..354196e9b5
--- /dev/null
+++ b/icons/Color/COPYING
@@ -0,0 +1,10 @@
+This work is licensed under the Creative Commons Attribution-ShareAlike
+4.0 International License. To view a copy of this license, visit
+http://creativecommons.org/licenses/by-sa/4.0/ or send a letter to
+Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
+
+This icon theme is more of an original work with inspiration from other
+FLOSS themes.
+
+When attributing the artwork, "GIMP team" is enough.
+Please link to https://www.gimp.org/ where available.
diff --git a/icons/Symbolic/COPYING b/icons/Symbolic/COPYING
new file mode 100644
index 0000000000..6e948737cf
--- /dev/null
+++ b/icons/Symbolic/COPYING
@@ -0,0 +1,16 @@
+This work is licenced under the Creative Commons Attribution-Share Alike 3.0
+United States License. To view a copy of this licence, visit
+http://creativecommons.org/licenses/by-sa/3.0/ or send a letter to Creative
+Commons, 171 Second Street, Suite 300, San Francisco, California 94105, USA.
+
+This icon theme is a derived work from the art-libre-symbolic theme made
+by the GNOME design team, taken in its 2015 form and modified since
+(including new icons, modified ones, possibly removed ones):
+https://github.com/gnome-design-team/gnome-icons/blob/master/art-libre-symbolic/src/art-libre.svg
+
+A few icons are taken (e.g. gimp-lock) or derived (gimp-lock-*) from the
+Adwaita icon theme as Creative Commons Attribution-Share Alike 3.0
+United States License as well.
+
+When attributing the artwork, "GNOME Project and GIMP team" is enough.
+Please link to https://www.gnome.org and https://www.gimp.org/ where available.