gst-plugin-scanner never completes in uninstalled environment

While attempting to work around #111, I've been trying to use gst-launch-1.0 in the uninstalled environment. When I do that, the command hangs while launching gst-plugin-scanner. GST_DEBUG=4 contains output like:

0:00:00.001213000 29820 0x7fed3fe05400 INFO            GST_REGISTRY gstregistry.c:1755:ensure_current_registry: reading registry cache: /Users/jdm/src/gst-build/build/registry.dat
0:00:00.002376000 29820 0x7fed3fe05400 INFO            GST_REGISTRY gstregistrybinary.c:584:priv_gst_registry_binary_read_cache: Unable to mmap file /Users/jdm/src/gst-build/build/registry.dat : Failed to open file “/Users/jdm/src/gst-build/build/registry.dat”: open() failed: No such file or directory
0:00:00.002423000 29820 0x7fed3fe05400 INFO            GST_REGISTRY gstregistrybinary.c:594:priv_gst_registry_binary_read_cache: Unable to read file /Users/jdm/src/gst-build/build/registry.dat : Failed to open file “/Users/jdm/src/gst-build/build/registry.dat”: No such file or directory
0:00:00.002431000 29820 0x7fed3fe05400 INFO            GST_REGISTRY gstregistry.c:1614:scan_and_update_registry: Validating plugins from registry cache: /Users/jdm/src/gst-build/build/registry.dat

As well as:

0:00:00.787606000 29821 0x7fc135505600 WARN      GST_PLUGIN_LOADING gstplugin.c:806:_priv_gst_plugin_load_file_for_registry: module_open failed: dlopen(/Users/jdm/src/gst-build/build/subprojects/gst-plugins-bad/ext/srt/libgstsrt.dylib, 2): Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib
  Referenced from: /usr/local/opt/srt/lib/libsrt.1.dylib
  Reason: image not found

(gst-plugin-scanner:29821): GStreamer-WARNING **: 13:09:52.215: Failed to load plugin '/Users/jdm/src/gst-build/build/subprojects/gst-plugins-bad/ext/srt/libgstsrt.dylib': dlopen(/Users/jdm/src/gst-build/build/subprojects/gst-plugins-bad/ext/srt/libgstsrt.dylib, 2): Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib
  Referenced from: /usr/local/opt/srt/lib/libsrt.1.dylib
  Reason: image not found
0

It ends with:

/Users/jdm/src/gst-build/subprojects/pygobject/gi/module.py:163: Warning: cannot register existing type 'GstEncodingProfile'
  g_type = info.get_g_type()
/Users/jdm/src/gst-build/subprojects/pygobject/gi/module.py:163: Warning: g_array_append_vals: assertion 'array' failed
  g_type = info.get_g_type()
/Users/jdm/src/gst-build/subprojects/pygobject/gi/module.py:163: Warning: g_hash_table_insert_internal: assertion 'hash_table != NULL' failed
  g_type = info.get_g_type()
/Users/jdm/src/gst-build/subprojects/pygobject/gi/module.py:163: Warning: g_once_init_leave: assertion 'result != 0' failed
  g_type = info.get_g_type()
/Users/jdm/src/gst-build/subprojects/pygobject/gi/module.py:163: Warning: g_type_register_static: assertion 'parent_type > 0' failed
  g_type = info.get_g_type()