Installed devel/valgrind and it compiles fine.

Run any program with valgrind and it shows no allocs at all.

valgrind -v ./leaking_program >/dev/null
==2780== Memcheck, a memory error detector
==2780== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.==2780== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
==2780== Command: ./leaking_program
==2780==
--2780-- Valgrind options:
--2780--    -v
--2780-- Contents of /proc/version:
--2780-- Arch and hwcaps: AMD64, amd64-sse3-cx16
--2780-- Page sizes: currently 4096, max supported 4096
--2780-- Valgrind library directory: /usr/local/lib/valgrind
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- Reading syms from /usr/local/lib/valgrind/memcheck-amd64-freebsd
--2780--    object doesn't have a symbol table
--2780--    object doesn't have a dynamic symbol table
--2780-- Scheduler: using generic scheduler lock implementation.
--2780-- Reading suppressions file: /usr/local/lib/valgrind/default.supp
==2780== embedded gdbserver: reading from /tmp/vgdb-pipe-from-vgdb-to-2780-by-robert-on-???
==2780== embedded gdbserver: writing to   /tmp/vgdb-pipe-to-vgdb-from-2780-by-robert-on-???
==2780== embedded gdbserver: shared mem   /tmp/vgdb-pipe-shared-mem-vgdb-2780-by-robert-on-???
==2780==
==2780== TO CONTROL THIS PROCESS USING vgdb (which you probably
==2780== don't want to do, unless you know exactly what you're doing,
==2780== or are doing some strange experiment):
==2780==   /usr/local/lib/valgrind/../../bin/vgdb --pid=2780 ...command...
==2780==
==2780== TO DEBUG THIS PROCESS USING GDB: start GDB like this
==2780==   /path/to/gdb ./batoh_bnb
==2780== and then give GDB the following command
==2780==   target remote | /usr/local/lib/valgrind/../../bin/vgdb --pid=2780
==2780== --pid is optional if only one valgrind process is running
==2780==
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
--2780-- WARNING: Serious error when reading debug info
--2780-- When reading debug info from [unknown]:
--2780-- failed to stat64/stat this file
==2780==
==2780== HEAP SUMMARY:
==2780==     in use at exit: 0 bytes in 0 blocks
==2780==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==2780==
==2780== All heap blocks were freed -- no leaks are possible
==2780==
==2780== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
==2780== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)


Also submitted bug to bitbucket valgrind-freebsd repository, but think this is better place to do so.
https://bitbucket.org/stass/valgrind-freebsd/issue/12/not-working-on-freebsd-10

First impression is that vki_kinfo_file structure is out of sync with current sys/user.h. But manually syncing, makes debug symbols load but lead to a crash. I will fill another PR for the crash since I dont think it is directly connected with this PR.

Fix: 

Sync vki_kinfo_file structure with kinfo_file in sys/user.h. Or update the includes to automaticly use system headers.
How-To-Repeat: on stable/10 run "valgrind -v any_program"