This may not be a good choice on MacOSX which doesn't consistently use pkgconfig.
More generally, I think it makes things worse if someone has curl in their standard
paths but doesn't have it configured in pkgconfig.
1 patch for repository darcs-unstable@darcs.net:screened:
Sat Sep 27 22:53:57 BST 2014 Ganesh Sittampalam <ganesh@earth.li>
* Control pkgconfig use with a flag, defaulted to off
It causes problems on e.g. MacOSX which doesn't have many pkgconfig files.