From d18bcbfa6885381f36f93dc819507c4d5e73e48d Mon Sep 17 00:00:00 2001
From: Jonah Beckford <71855677+jonahbeckford@users.noreply.github.com>
Date: Fri, 21 Jul 2023 19:17:55 -0700
Subject: [PATCH] Support MSVC compiler

- No assuming -lpthread and -O2 -fPIC
  are valid for all compilers
- This commit/PR fixes the release profile
   only, and does not touch the -Wextra
   used in the dev profile that is invalid
   in MSVC
---
 CHANGES.md             |  4 ++++
 src/config/discover.ml | 16 +++++++++++++++-
 src/dune               |  4 ++--
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index e05d657..d06b465 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,7 @@
+### Pending
+
+  * Don't use `-lpthread` and non-MSVC flags with MSVC compiler
+
 ### 5.1.0 (2021-09-22)
 
   * Added let&-operator for implicit closing of an opened database.
diff --git a/src/config/discover.ml b/src/config/discover.ml
index df544bd..0976904 100644
--- a/src/config/discover.ml
+++ b/src/config/discover.ml
@@ -66,9 +66,23 @@ let split_ws str =
   done;
   List.rev !lst
 
+let add_compiler_args ~is_msvc ~cflags ~libs =
+  let module C = Configurator.V1 in
+  match is_msvc with
+  | true -> {
+      C.Pkg_config.cflags = cflags @ ["/O2"];
+      libs }
+  | false -> {
+      C.Pkg_config.cflags = cflags @ ["-O2"; "-fPIC"; "-DPIC"];
+      libs = libs @ ["-lpthread"] }
+
 let () =
   let module C = Configurator.V1 in
   C.main ~name:"sqlite3" (fun c ->
+    let is_msvc =
+      opt_map (C.ocaml_config_var c "ccomp_type") ~default:false
+        ~f:(function "msvc" -> true | _ -> false)
+    in
     let is_macosx =
       opt_map (C.ocaml_config_var c "system") ~default:false
         ~f:(function "macosx" -> true | _ -> false)
@@ -92,6 +106,6 @@ let () =
       | [libs] -> split_ws libs
       | _ -> failwith "pkg-config failed to return libs"
     in
-    let conf = { C.Pkg_config.cflags; libs } in
+    let conf = add_compiler_args ~is_msvc ~cflags ~libs in
     C.Flags.write_sexp "c_flags.sexp" conf.cflags;
     C.Flags.write_sexp "c_library_flags.sexp" conf.libs)
diff --git a/src/dune b/src/dune
index 2b9a0d2..e821415 100644
--- a/src/dune
+++ b/src/dune
@@ -3,8 +3,8 @@
   (foreign_stubs
     (language c)
     (names sqlite3_stubs)
-    (flags (:standard) (:include c_flags.sexp) -O2 -fPIC -DPIC))
-  (c_library_flags (:include c_library_flags.sexp) -lpthread)
+    (flags (:standard) (:include c_flags.sexp)))
+  (c_library_flags (:include c_library_flags.sexp))
 )
 
 (rule