setup 2.920 release candidate - please test

[Jon Turney]

A new setup release candidate is available at:

  https://cygwin.com/setup/setup-2.920.x86_64.exe (64 bit version)
  https://cygwin.com/setup/setup-2.920.x86.exe    (32 bit version)

Please test, and report any problems here.

This is not the place for setup feature requests.


Changes compared to 2.919:

- Add perpetual support for preremove scripts (thanks to Christian Franke)

- Major update to libsolv (from 0.6.29 to 0.7.22)

- Allow packages to be marked as 'self-destruct'


For instructions on obtaining and building the source code for setup, 
see https://sourceware.org/cygwin-apps/setup.html

Please send bug reports, as usual, to the public mailing list cygwin AT 
cygwin DOT com.