Undefined symbols when building with -race

I get the following on my Ubuntu machine:

```
$ go build -race
# _/home/utilisateur/git/go-random/random
runtime.raceinit: __tsan_init: not defined
runtime.raceinit: __tsan_map_shadow: not defined
runtime.racefini: __tsan_fini: not defined
runtime.racemapshadow: __tsan_map_shadow: not defined
runtime.racemalloc: __tsan_malloc: not defined
runtime.racegostart: __tsan_go_start: not defined
runtime.racegoend: __tsan_go_end: not defined
runtime.raceacquireg: __tsan_acquire: not defined
runtime.racereleaseg: __tsan_release: not defined
runtime.racereleasemergeg: __tsan_release_merge: not defined
runtime.racefingo: __tsan_finalizer_goroutine: not defined
runtime.RaceDisable: __tsan_go_ignore_sync_begin: not defined
runtime.RaceEnable: __tsan_go_ignore_sync_end: not defined
runtime.raceread: __tsan_read: not defined
runtime.racereadpc: __tsan_read_pc: not defined
runtime.racewrite: __tsan_write: not defined
runtime.racewritepc: __tsan_write_pc: not defined
runtime.racereadrange: __tsan_read_range: not defined
runtime.racereadrangepc1: __tsan_read_range: not defined
runtime.racewriterange: __tsan_write_range: not defined
runtime.racewriterangepc1: __tsan_write_range: not defined
/usr/lib/go/pkg/tool/linux_amd64/link: too many errors
```

It looks like a packaging bug in my go1.5.1 package:

https://bugs.launchpad.net/ubuntu/+source/golang-race-detector-runtime/+bug/1487010