[libxml2] Add CI job for static build

[Nick Wellnhofer <nwellnhof src gnome org>]

commit f0ba4da18c17d3f1dd73007ce0888c978319e6f1
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sun Apr 3 14:30:03 2022 +0200

    Add CI job for static build

 .gitlab-ci.yml | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 9029cf64..eb11a3d2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -34,6 +34,12 @@ gcc:python3:
     CFLAGS: "-O2"
     PYTHON: "/usr/bin/python3"
 
+gcc:static:
+  extends: .test
+  variables:
+    CONFIG: "--disable-shared --without-python"
+    CFLAGS: "-O2"
+
 clang:asan:
   extends: .test
   variables: