By default duplicate non-static symbols loaded by dynamic libraries are
de-duplicated by the dynamic library loader. This can lead to issues
with statically linked libraries inside obs plugins if the symbols
share their signature: Whichever plugin is loaded first gets to "set"
the symbol (which can become problematic especially for C++ template
functions).
Using RTLD_LOCAL ensures that all symbols are hidden and can only be
explicitly loaded using dlsym() which avoids this issue.
Unfortunately due to the way scripting works in obs-studio, Python
still needs to be loaded with RTLD_GLOBAL, hence the branch in the fix.