[gimp/wip/schumaml/add-ci-prepare-stage] build: make sure CI clang build has an apt-cache directory

[Michael Schumacher <schumaml src gnome org>]

commit 001244969b1c9a93e6b44d3f59606b5d50792df1
Author: Michael Schumacher <schumaml gmx de>
Date:   Fri May 29 17:51:41 2020 +0200

    build: make sure CI clang build has an apt-cache directory

 .gitlab-ci.yml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 64c7240fb3..dffdcd78d3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -140,6 +140,7 @@ gimp-debian/testing-clang:
     CC: "clang"
     CXX: "clang++"
   script:
+    - mkdir -p "$APT_CACHE"
     - apt-get install -y --no-install-recommends -o dir::cache::archives="$APT_CACHE"
         clang libomp-dev
     - meson _build