[gegl] operations: json operations - copy into build so they are available for tests/docs

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

commit 0a07877131a8008b3e861c03705c03d38a6cd20b
Author: John Marshall <jtm home gmail com>
Date:   Tue Jun 16 15:16:50 2020 +0100

    operations: json operations
     - copy into build so they are available for tests/docs

 operations/json/meson.build | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)
---
diff --git a/operations/json/meson.build b/operations/json/meson.build
index 1d861ecca..feab852ba 100644
--- a/operations/json/meson.build
+++ b/operations/json/meson.build
@@ -1,3 +1,16 @@
-install_data('grey2.json',
-  install_dir: get_option('libdir') / api_name,
-)
+
+json_operations = [
+  'grey2.json',
+  'dropshadow2.json'
+]
+
+# copy json files into build so they are available for tests/docs
+foreach _file : json_operations
+  json_operations += configure_file(
+    input: _file,
+    output: _file,
+    copy: true,
+    install: true,
+    install_dir: get_option('libdir') / api_name,
+  )
+endforeach