-custom under NT

[Don Syme <dsyme@microsoft.com>]

I'm having problems using -custom under Windows NT.  With test.ml
containing just

let x = 1;;


ocamlc  -c test.ml
ocamlc  -verbose -o test  -custom unix.cma  -cclib -lunix test.cmo

gives

+ cl /nologo /MT /Fetest.exe -Ic:/ocaml/lib  C:\TEMP\camlprim0.c -lunix
c:/ocaml/lib\libcamlrun.lib
Command line warning D4002 : ignoring unknown option '-lunix'
camlprim0.c
camlprim0.obj : error LNK2001: unresolved external symbol _win_stdhandle
camlprim0.obj : error LNK2001: unresolved external symbol _win_startup
camlprim0.obj : error LNK2001: unresolved external symbol _win_cleanup
etc.

Changing -cclib -lunix to -ccopt gives a different set of errors:

ocamlc -verbose -g -o test  -custom unix.cma  -ccopt
c:/ocaml/lib/libunix.lib  test.cmo

+ cl /nologo /MT /Fetest.exe -Ic:/ocaml/lib c:/ocaml/lib/libunix.lib
C:\TEMP\camlprim0.c  c:/ocaml/lib\libcamlrun.lib
camlprim0.c
libunix.lib(startup.obj) : error LNK2001: unresolved external symbol
_WSAStartup@8
libunix.lib(startup.obj) : error LNK2001: unresolved external symbol
_WSACleanup@0
libunix.lib(socket.obj) : error LNK2001: unresolved external symbol
_WSAGetLastError@0
etc.

What am I doing wrong, or what should I try next?

(P.S. The notes for -custom under Windows could mention how to set up the
paths
for VC++ so ocaml can find the command line VC++ compiler. )

Thanks!
Don Syme