/usr/local/bin symbolic link disappears every time cyg setup is run

[Dat Head]

I have a symlink from /usr/local/bin to /3TB-external/bin/CYGWIN to keep
architecture independent bin files on an external drive for portability.

every time I run cyg setup.exe it removes the symlink and creates an
empty /usr/local/bin directory - is it really supposed to do that?
are there some cygwin pkgs (none that I have installed because it has
never put anything there) that put files there? (even if there are,
it shouldn't zap the symlink)

Cygwin 1.7.30-1

CYGWIN_NT-6.1 frog2 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64 Cygwin

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