1.7.1 --shared-zlib fails

[Nibbler999]

#1335 introduced a bug with option handling, it's using code like:

if b(options.shared_zlib) == True:

b returns 'true' or 'false' as a string and 'true' != True, so any builds using --shared-zlib currently fail with a linker error.

[jbergstroem]

My bad. See #1429 for a fix. Especially commit 867de71.

[Fishrock123]

Fixed in 1.8.1