[gegl] tests: add option to set tests as parallel

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

commit 71d1817c143ca6c2947b62f510c41073bf7a7cc7
Author: John Marshall <jtm home gmail com>
Date:   Mon Jan 11 12:01:35 2021 +0000

    tests: add option to set tests as parallel

 meson_options.txt | 6 ++++++
 tests/meson.build | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/meson_options.txt b/meson_options.txt
index 54d2df00e..a0ad69454 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -20,6 +20,12 @@ option('vapigen',
   value: 'auto',
   description: 'Vala .vapi generation - depends on introspection'
 )
+# Build settings
+option('parallel-tests',
+  type: 'boolean',
+  value: 'true',
+  description: 'run tests in parallel or sequentially'
+)
 
 # optional dependencies
 option('gdk-pixbuf',    type: 'feature', value: 'auto')
diff --git a/tests/meson.build b/tests/meson.build
index e515ab060..c9712c935 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -31,7 +31,7 @@ gegl_test_deps = [
 ]
 
 # common test paralllel flag
-gegl_test_parallel = true
+gegl_test_parallel = get_option('parallel-tests')
 
 
 # Tests