Update windows cross-compilation instructions and scripts

INSTALL

@@ -91,10 +91,10 @@ To build a Windows (win64) executable on Linux/MacOsX:
         brew install mingw-w64 gawk
 
         opam repository add windows git://github.com/ocaml-cross/opam-cross-windows
-        opam switch 4.04.0
+        opam switch 4.08.0
         eval `opam config env`
 
-        opam install ocaml-windows ocamlfind camlp5
+        opam install ocaml-windows64 sedlex-windows easy-format-windows
 
 2. Build
 

Makefile

@@ -24,10 +24,13 @@ endif
 
 
 deps: build-dir
-	@#$(MAKE) -C deps download
-	@#$(MAKE) -C deps
-	@#$(MAKE) -C deps uninstall install
+ifndef OCAMLFIND_TOOLCHAIN
 	opam install -y --deps-only ./opam
+else
+	$(MAKE) -C deps download
+	$(MAKE) -C deps
+	$(MAKE) -C deps uninstall install
+endif
 
 
 build-dir:
@@ -48,7 +51,7 @@ install:
 # especially useful for cross-compilation
 STRIP ?= strip
 strip:
-	$(STRIP) src/piqi
+	$(STRIP) src/piqi$(EXE)
 
 
 # re-generate _piqi.ml from .piqi and copy the latest version of piqilib.ml  --

configure

@@ -104,6 +104,7 @@ then
 
     # figure out which dependencies we need to build
     echo "checking whether necessary dependencies are already installed..."
+    export OCAMLFIND_TOOLCHAIN=$TOOLCHAIN
     for i in xmlm easy-format base64
     do
         dir="`$OCAMLFIND query $i 2>/dev/null`"