This change reduces the risk of LADSPA plugins referencing
Audacity symbols by using the RTLD_DEEPBIND flag when loading
the plugins.
It also addresses an issue specific to the "blop" plugins where
they load their own libraries (without RTLD_DEEPBIND).
A much better solution would be to change Audacity's default
symbol visibility to "hidden" which would expose ONLY symbols
specificially marked as visible.
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