Add the right file...

.gitlab-ci.yml

-image: php 5.4-cli
+before_script:
+  - apt-get clean
+  - apt-get update
+  - apt-get install -y php5-cli
 
 syntax:
   script:
   - php -l htdocs/index.php
-  - php -l components/*.php
-  - php -l plugins/*.php
-  - php -l lib/*.php
\ No newline at end of file
+  - find components | xargs -n 1 php -l
+  - find plugins | xargs -n 1 php -l
+  - find lib | xargs -n 1 php -l
\ No newline at end of file