piros/tor: Code added to Tor to support PIR-based onion service descriptor lookups @ efc8b2dbbfa0659405edb1e388f1f84cb8023425

Nick Mathewson 45b911b79b Add pkg.m4 to use pkgconfig macros		10 lat temu
..
ax_check_sign.m4	0e597471af Use a nicely written autoconf macro to determine the sign of a type	11 lat temu
pc_from_ucontext.m4	2662885aa9 Use pc_from_ucontext.m4 from Google Performance Tools	11 lat temu
pkg.m4	45b911b79b Add pkg.m4 to use pkgconfig macros	10 lat temu