[gegl] subprojects/libnsgif: add update shell script

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

commit 002f4807e511e65c885cb7c10643b6f44a514eb3
Author: Michael Drake <michael drake codethink co uk>
Date:   Wed Mar 16 08:54:50 2022 +0000

    subprojects/libnsgif: add update shell script
    
    Run this to simplify making updates in future.

 subprojects/libnsgif/update.sh | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
---
diff --git a/subprojects/libnsgif/update.sh b/subprojects/libnsgif/update.sh
new file mode 100755
index 000000000..bbb7854aa
--- /dev/null
+++ b/subprojects/libnsgif/update.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+
+UPSTREAM="https://source.netsurf-browser.org/libnsgif.git";
+LOCAL="temp"
+
+git clone "$UPSTREAM" "$LOCAL"
+
+echo "Copying sources"
+cp "$LOCAL"/COPYING .
+cp "$LOCAL"/README.md .
+cp "$LOCAL"/include/nsgif.h .
+cp "$LOCAL"/src/gif.c .
+cp "$LOCAL"/src/lzw.c .
+cp "$LOCAL"/src/lzw.h .
+
+echo "Upstream: $UPSTREAM"
+echo "Ref: `git -C "$LOCAL" rev-parse HEAD`"
+
+rm -rf "$LOCAL"