people how to get even more details shown

these days since the c_rehash tool is written (fixed) to do the proper
action even on file systems that don't support symlinks.

made it cause less compiler warnings
made it require 7.9.7 to build

is used.

up-to-date with recent changes.

removed old section about problems with old autoconfs, I don't think that
happens anymore

for storage and retrieval of private data in the curl handle.