try to depend on libgl at test time only

recipes/ocpsvg/meta.yaml

@@ -37,6 +37,15 @@ test:
     - pytest -v tests/
   requires:
     - pytest
+    # The libgl dependency for the test section can likely be removed when
+    # the following https://github.com/conda-forge/ocp-feedstock/pull/50
+    # gets merged in the ocp feedstock
+    # this helps avoid a yum dependency
+    # either with the yum dependency or with this, the end user is assumed
+    # to have X11 system dependencies installed
+    # this helps the user avoid to have a direct dependency on libgl
+    # from this package (it will be transitive from OCP once the PR gets merged)
+    - libgl    # [linux]
 
 about:
   license: Apache-2.0