Install needed folders for snapshot

.gitattributes

@@ -103,7 +103,11 @@ yacc/*.[ch]   ocaml-typo=long-line,very-long-line,unused-prop
 *.precheck text eol=lf
 *.runner text eol=lf
 
+clone-flexdll text eol=lf 
 configure text eol=lf
+configure-windows text eol=lf
+esy-configure text eol=lf
+esy-build text eol=lf
 config/auto-aux/hasgot text eol=lf
 config/auto-aux/hasgot2 text eol=lf
 config/auto-aux/runtest text eol=lf

clone-flexdll

@@ -0,0 +1,16 @@
+#! /bin/sh
+
+# clone-flexdll
+#
+# Brings in flexdll, if necessary
+
+if [ -d "flexdll" ]; then
+    echo "[Flexdll] Already present, no need to clone."
+else
+    echo "[Flexdll] Cloning..."
+    git clone https://github.com/esy-ocaml/flexdll.git
+    cd flexdll
+    git checkout f84baaeae463f96f9582883a9cfb7dd1096757ff
+    cd ..
+    echo "[Flexdll] Clone successful!"
+fi

config/Makefile.mingw64

@@ -32,7 +32,7 @@ BINDIR=$(PREFIX)/bin
 BYTERUN=ocamlrun
 
 ### Where to install the standard library
-LIBDIR=$(PREFIX)/lib
+LIBDIR=$(PREFIX)/lib/ocaml
 
 ### Where to install the stub DLLs
 STUBLIBDIR=$(LIBDIR)/stublibs

configure-windows

@@ -0,0 +1,34 @@
+#! /bin/sh
+
+# configure-windows
+#
+# Creates a native Windows MingW build, based on:
+# https://github.com/ocaml/ocaml/blob/trunk/README.win32.adoc
+
+
+export prefix=C:/ocamlmgw64
+while : ; do
+    case "$1" in
+        "") break;;
+        -prefix|--prefix)
+            prefix=$2; shift;;
+    esac
+    shift
+done
+
+echo "[configure-windows] Prefix path: $prefix"
+
+echo "[configure-windows] Copying architecture headers."
+cp config/m-nt.h byterun/caml/m.h
+cp config/s-nt.h byterun/caml/s.h
+
+# TODO: Differentiate based on architecture - use 'Makefile.mingw' for 32-bit environments
+echo "[configure-windows] Bringing over mingw64 Makefile."
+cp config/Makefile.mingw64 config/Makefile
+
+echo "[configure-windows] Replace prefix path with: $prefix."
+sed -i "s#PREFIX=C:/ocamlmgw64#PREFIX=$prefix#g" config/Makefile
+
+echo "[configure-windows] Setting up flexdll"
+./clone-flexdll
+make flexdll

esy-build

@@ -0,0 +1,24 @@
+#! /bin/bash
+
+# esy-build
+#
+# Wrapper to execute appropriate build strategy, based on platform
+
+set -u
+set -e
+set -o pipefail
+
+case "$(uname -s)" in
+    CYGWIN*|MINGW32*|MSYS*)
+        echo "[esy-build] Detected windows environment..."
+        make -j1 world.opt
+        make flexlink.opt
+        ;;
+    *)
+        echo "[esy-build] Detected OSX / Linux environment"
+        make -j4 world.opt
+        ;;
+esac
+
+# Common build steps
+make install

esy-configure

@@ -0,0 +1,29 @@
+#! /bin/bash
+
+# esy-configure
+#
+# Wrapper to delegate to configuration to the 
+# appropriate `configure` strategy based on the active platform.
+#
+# Today, OCaml has separate build strategies:
+# - Linux, OSX, Cygwin (gcc) - https://github.com/ocaml/ocaml/blob/trunk/INSTALL.adoc
+# - Windows, Cygin (mingw) - https://github.com/ocaml/ocaml/blob/trunk/README.win32.adoc
+#
+# We want `esy` to work cross-platform, so this is a shim script that will delegate to the
+# appropriate script depending on the platform. We assume that if the platform is `CYGWIN`
+# that the `mingw` (native executable) strategy is desired.
+
+set -u
+set -e
+set -o pipefail
+
+case "$(uname -s)" in
+    CYGWIN*|MINGW32*|MSYS*)
+        echo "[esy-configure] Detected windows environment..."
+        ./configure-windows "$@"
+        ;;
+    *)
+        echo "[esy-configure] Detected OSX / Linux environment"
+        ./configure "$@"
+        ;;
+esac

package.json

@@ -4,11 +4,50 @@
   "description": "BuckleScript's OCaml Compiler as an npm Package",
   "esy": {
     "build": [
-      "./configure -no-cfi -prefix $cur__install",
-      "make -j world.opt"
-    ],
-    "install": [
-      "make install"
+      "./esy-configure -no-cfi -prefix #{self.install}",
+      "./esy-build",
+      [
+        "cp",
+        "-r",
+        "-f",
+        "#{self.root / 'utils'}",
+        "#{self.install / 'utils'}"
+      ],
+      [
+        "cp",
+        "-r",
+        "-f",
+        "#{self.root / 'parsing'}",
+        "#{self.install / 'parsing'}"
+      ],
+      [
+        "cp",
+        "-r",
+        "-f",
+        "#{self.root / 'typing'}",
+        "#{self.install / 'typing'}"
+      ],
+      [
+        "cp",
+        "-r",
+        "-f",
+        "#{self.root / 'bytecomp'}",
+        "#{self.install / 'bytecomp'}"
+      ],
+      [
+        "cp",
+        "-r",
+        "-f",
+        "#{self.root / 'driver'}",
+        "#{self.install / 'driver'}"
+      ],
+      [
+        "cp",
+        "-r",
+        "-f",
+        "#{self.root / 'tools'}",
+        "#{self.install / 'tools'}"
+      ]
     ],
     "buildsInSource": true,
     "exportedEnv": {