Import pstack-1.2
Apply http://people.freebsd.org/~jhb/patches/pstack_threads.patch
Fix build on amd64
Get rid of procfs
Remove libc_r support
Remove support for FreeBSD older than 6.0
Simplify Makefile
Make gVerbose static
Remove -n option

It was possible to use this option only with procfs.
Fix warning
Option -d require file argument
Remove old workarounds for ptrace(2)
Adjust the man page that pstack now supports 64-bit executables
Check that process is really stopped
Use comparison in if statement
Fix compiler warning
Fix compiler format warnings
Fix more warnings
More pretty printing