[master] added usual shared library trick for python tests

this should solve test failure on MacOS.  committing at my discretion.

src/lib/python/isc/sysinfo/tests/Makefile.am

@@ -2,6 +2,12 @@ PYCOVERAGE_RUN = @PYCOVERAGE_RUN@
 PYTESTS = sysinfo_test.py
 EXTRA_DIST = $(PYTESTS)
 
+# If necessary (rare cases), explicitly specify paths to dynamic libraries
+# required by loadable python modules.
+if SET_ENV_LIBRARY_PATH
+LIBRARY_PATH_PLACEHOLDER = $(ENV_LIBRARY_PATH)=$(abs_top_builddir)/src/lib/dns/.libs:$(abs_top_builddir)/src/lib/log/.libs:$(abs_top_builddir)/src/lib/config/.libs:$(abs_top_builddir)/src/lib/util/.libs:$(abs_top_builddir)/src/lib/datasrc/.libs:$$$(ENV_LIBRARY_PATH)
+endif
+
 # test using command-line arguments, so use check-local target instead of TESTS
 check-local:
 if ENABLE_PYTHON_COVERAGE
@@ -11,6 +17,7 @@ if ENABLE_PYTHON_COVERAGE
 endif
 	for pytest in $(PYTESTS) ; do \
 	echo Running test: $$pytest ; \
+	$(LIBRARY_PATH_PLACEHOLDER) \
 	PYTHONPATH=$(COMMON_PYTHON_PATH) \
 	$(PYCOVERAGE_RUN) $(abs_srcdir)/$$pytest || exit ; \
 	done