[libxml2] Fix Python tests on macOS

[Nick Wellnhofer <nwellnhof src gnome org>]

commit d8f05db8f695d46c1ba83c97ec474be56c19c432
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sat May 14 22:28:19 2022 +0200

    Fix Python tests on macOS

 python/tests/Makefile.am | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/python/tests/Makefile.am b/python/tests/Makefile.am
index 7bb6828a..c2270ce5 100644
--- a/python/tests/Makefile.am
+++ b/python/tests/Makefile.am
@@ -64,6 +64,7 @@ check-local:
        @echo "## running Python regression tests"
        @(export PYTHONPATH="..:../.libs:$(srcdir)/..:$$PYTHONPATH" ; \
          export LD_LIBRARY_PATH="$(top_builddir)/.libs:$$LD_LIBRARY_PATH" ; \
+         export DYLD_LIBRARY_PATH="$(top_builddir)/.libs:$$DYLD_LIBRARY_PATH" ; \
          export PATH="$(top_builddir)/.libs:$$PATH" ; \
          for test in $(PYTESTS) ; do \
            log=`$(PYTHON) $(srcdir)/$$test` ; \