Add MSVC libNAME.lib and dllNAME.dll to stub libraries

[jonahbeckford]

Setup:

• MSVC
• OCaml 4.14.0
• Dune (latest from main branch; bleeding edge 3.7)
• What is being built ... the ctypes-foreign (library ...) from dune-universe

Problem

In the examples below I was getting the following when trying to link with ctypes_foreign.cma:

** Fatal error: Cannot find file "-lctypes_foreign_stubs"

#119 explains why MSVC does not use -lLIBRARY but instead uses libLIBRARY.lib. In there a msvc_hack_cclibs function is introduced to transform libraries when passing to ocamlc with -cclib.

I guess by mistake msvc_hack_cclibs was never applied to stub libraries.

Before PR

Actual targets:
- _build/default/src/ctypes-foreign/ctypes_foreign.cma
Running[1]: (cd _build/default && Z:\source\dkml-compiler\_opam\bin\ocamlc.opt.exe 
-w @1..3@5..28@30..39@43@46..47@49..57@61..62-40 -strict-sequence -strict-formats -short-paths 
-keep-locs -principal -g -a -o src/ctypes-foreign/ctypes_foreign.cma 
-dllib -lctypes_foreign_stubs 
-cclib -lctypes_foreign_stubs 
-cclib -LZ:/source/bogue/_cpkgs/bin/../lib 
-cclib libffi.lib 
-cclib psapi.lib 
src/ctypes-foreign/.ctypes_foreign.objs/byte/libffi_abi.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_closure_properties.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_ffi_stubs.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_weak_ref.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_ffi.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/dl.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_foreign_basis.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_foreign_threaded_stubs.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/foreign.cmo)

After PR

The first -dllib and the first -cclib have changed correctly.

Actual targets:
- _build/default/src/ctypes-foreign/ctypes_foreign.cma
Running[1]: (cd _build/default && Z:\source\dkml-compiler\_opam\bin\ocamlc.opt.exe 
-w @1..3@5..28@30..39@43@46..47@49..57@61..62-40 -strict-sequence -strict-formats -short-paths 
-keep-locs -principal -g -a -o src/ctypes-foreign/ctypes_foreign.cma 
-dllib dllctypes_foreign_stubs.dll
-cclib libctypes_foreign_stubs.lib
-cclib -LZ:/source/bogue/_cpkgs/bin/../lib 
-cclib libffi.lib 
-cclib psapi.lib 
src/ctypes-foreign/.ctypes_foreign.objs/byte/libffi_abi.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_closure_properties.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_ffi_stubs.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_weak_ref.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_ffi.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/dl.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_foreign_basis.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/ctypes_foreign_threaded_stubs.cmo 
src/ctypes-foreign/.ctypes_foreign.objs/byte/foreign.cmo)

For later ... not in this PR

The

-cclib libctypes_foreign_stubs.lib
-cclib -LZ:/source/bogue/_cpkgs/bin/../lib -cclib libffi.lib 
-cclib psapi.lib 

should really be:

-cclib -LZ:/source/dkml-compiler/_opam/ctypes-foreign
-cclib libctypes_foreign_stubs.lib
-cclib -LZ:/source/bogue/_cpkgs/bin/../lib -cclib libffi.lib 
-cclib psapi.lib 

Without the -L I get the following when I try to use the resulting ctypes_foreign.cma:

** Fatal error: Cannot find file "libctypes_foreign_stubs.lib"

[jonahbeckford]

This issue may be a side-effect of a latent bug in the OCaml compiler toolchain, which could be (or should be) aware of -lLIBNAME syntax (and convert to proper MSVC syntax) when it processes .cm[x]a files.

For now I'll stick the label "postponed" until this issue gets a good review.

[rgrinberg]

Please re-open if this is relevant and the PR is in a good state to be reviewed.