[gimp-help/gimp-help-2-10] gitlab-ci: set BUILD_DIR when building inside web/.

[Jehan <jehanp src gnome org>]

commit c23c99aed8c334bf4ba5bd0ffe8ae7b2b46b872b
Author: Jehan <jehan girinstud io>
Date:   Wed Feb 23 16:55:44 2022 +0100

    gitlab-ci: set BUILD_DIR when building inside web/.
    
    Otherwise the html/ folder will end up into /html/ (under the root), not
    current dir.
    
    Fixes in CI:
    
    > mv: cannot stat 'html/': No such file or directory

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d5e1ee706..80607525d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -36,6 +36,6 @@ build-debian:
     - make && make install
     - mv ${INSTALL_PREFIX}/share/gimp/2.0/help/ ../www/
     - cd ../web
-    - make
+    - BUILD_DIR='.' make
     - mv html/ ../html/
   timeout: 2 hours