[gegl] libs/libnsgif: add libnsgif files to tarball

[Øyvind "pippin" Kolås <ok src gnome org>]

commit bf9b962935c5e947bff85a2bff596aaf276eaad5
Author: Øyvind Kolås <pippin gimp org>
Date:   Wed Sep 19 15:22:18 2018 +0200

    libs/libnsgif: add libnsgif files to tarball

 libs/Makefile.am | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/libs/Makefile.am b/libs/Makefile.am
index 176d34787..4c69885c3 100644
--- a/libs/Makefile.am
+++ b/libs/Makefile.am
@@ -1 +1,9 @@
 SUBDIRS = rgbe poly2tri-c
+
+EXTRA_DIST = libnsgif/libnsgif.c \
+libnsgif/libnsgif.h \
+libnsgif/libnsgif.pc.in \
+libnsgif/log.h \
+libnsgif/lzw.h \
+libnsgif/lzw.c
+