[gtk/wip/smcv/roaring-license] Move roaring bitmaps code to gtk/roaring/ and add a README

[Simon McVittie <smcv src gnome org>]

commit eb6bd20bd7d328079cca707cdd9f8df4cfe199b5
Author: Simon McVittie <smcv debian org>
Date:   Sat Aug 8 16:17:59 2020 +0100

    Move roaring bitmaps code to gtk/roaring/ and add a README
    
    As suggested by Matthias Clasen on gtk!2408. This keeps the
    Apache-licensed stuff together.
    
    As per the discussion on gtk!2408 and gtk!2409, replacing this with
    upstream CRoaring is specifically not supported by the GTK maintainers.
    
    Signed-off-by: Simon McVittie <smcv debian org>

 COPYING.Apache-2.0 => gtk/roaring/COPYING |  0
 gtk/roaring/README.md                     | 12 ++++++++++++
 gtk/{ => roaring}/roaring.c               |  0
 gtk/{ => roaring}/roaring.h               |  0
 4 files changed, 12 insertions(+)
---
diff --git a/COPYING.Apache-2.0 b/gtk/roaring/COPYING
similarity index 100%
rename from COPYING.Apache-2.0
rename to gtk/roaring/COPYING
diff --git a/gtk/roaring/README.md b/gtk/roaring/README.md
new file mode 100644
index 0000000000..c1a3c617fc
--- /dev/null
+++ b/gtk/roaring/README.md
@@ -0,0 +1,12 @@
+Roaring bitmaps implementation
+==============================
+
+This directory contains a version of the Roaring bitmaps reference
+implementation (CRoaring) which has been modified for GTK.
+
+It is not necessarily compatible with past or future versions of CRoaring,
+and replacing it with a different version or linking to a system copy
+is not supported.
+
+See the source files for copyright and licensing information, and the
+`COPYING` file for the full text of the Apache license, version 2.0.
diff --git a/gtk/roaring.c b/gtk/roaring/roaring.c
similarity index 100%
rename from gtk/roaring.c
rename to gtk/roaring/roaring.c
diff --git a/gtk/roaring.h b/gtk/roaring/roaring.h
similarity index 100%
rename from gtk/roaring.h
rename to gtk/roaring/roaring.h