go version go1.6.2 darwin/amd64

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH=""
GORACE=""
GOROOT="/opt/local/lib/go"
GOTOOLDIR="/opt/local/lib/go/pkg/tool/darwin_amd64"
GO15VENDOREXPERIMENT="1"
CC="/usr/bin/clang"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fno-common"
CXX="clang++"
CGO_ENABLED="1"

link: warning: option -X github.com/mongodb/mongo-tools/common/options.Gitspec -X may not work in future releases; use -X github.com/mongodb/mongo-tools/common/options.Gitspec=-X
usage: link [options] main.o
  -B note
        add an ELF NT_GNU_BUILD_ID note when using ELF
  -C    check Go calls to C code
  -D address
        set data segment address (default -1)
  -E entry
        set entry symbol name
  -H type
        set header type
  -I linker
        use linker as ELF dynamic linker
  -L directory
        add specified directory to library path
  -R quantum
        set address rounding quantum (default -1)
  -T address
        set text segment address (default -1)
  -V    print version and exit
  -X definition
        add string value definition of the form importpath.name=value
  -a    disassemble output
  -buildid id
        record id as Go toolchain build id
  -buildmode mode
        set build mode
  -c    dump call graph
  -cpuprofile file
        write cpu profile to file
  -d    disable dynamic executable
  -extar string
        archive program for buildmode=c-archive
  -extld linker
        use linker when linking in external mode
  -extldflags flags
        pass flags to external linker
  -f    ignore version mismatch
  -g    disable go package data checks
  -h    halt on error
  -installsuffix suffix
        set package directory suffix
  -k symbol
        set field tracking symbol
  -libgcc string
        compiler support lib for internal linking; use "none" to disable
  -linkmode mode
        set link mode (internal, external, auto)
  -linkshared
        link against installed Go shared libraries
  -memprofile file
        write memory profile to file
  -memprofilerate rate
        set runtime.MemProfileRate to rate
  -msan
        enable MSan interface
  -n    dump symbol table
  -o file
        write output to file
  -r path
        set the ELF dynamic linker search path to dir1:dir2:...
  -race
        enable race detector
  -s    disable symbol table
  -shared
        generate shared object (implies -linkmode external)
  -tmpdir directory
        use directory for temporary files
  -u    reject unsafe packages
  -v    print link trace
  -w    disable DWARF generation