make.fsx: implement the 'reinstall' target in Win

For easier development experience.

TODO: implement same for unix, but maybe when we get rid of
legacy framework support, so that we can just adopt make.fsx
(instead of having install.sh for mac/linux like it's
happening now).

Makefile

@@ -7,5 +7,9 @@ release:
 install: release
 	./scripts/install.sh
 
+reinstall:
+	echo "'reinstall' target not supported yet in Unix, uninstall manually and use 'install' for now" >> /dev/stderr
+	exit 1
+
 check:
 	./scripts/runTests.fsx

scripts/make.fsx

@@ -212,24 +212,17 @@ let finalReleaseFolderPath = Path.Combine(releaseFolderPath, "net6.0")
 let finalReleaseFolderPath = releaseFolderPath
 #endif
 
-match maybeTarget with
-
-| None
-| Some "all" -> MakeAll() |> ignore
-
-| Some "release" ->
-    let buildConfig = BinaryConfig.Release
-    JustBuild buildConfig
-
-| Some "install" ->
+let Install (isReinstall: bool) =
     let buildConfig = BinaryConfig.Release
     JustBuild buildConfig
 
     if fsxInstallationDir.Exists then
-         // TODO
-        failwithf
-            "Existing installation found in '%s'. This script can't overwrite an existing installation yet"
-            fsxInstallationDir.FullName
+        if not isReinstall then
+            failwithf
+                "Existing installation found in '%s'. Consider using the target 'reinstall' instead of 'install'."
+                fsxInstallationDir.FullName
+        else
+            fsxInstallationDir.Delete true
 
     Console.WriteLine "Installing..."
     Console.WriteLine()
@@ -322,6 +315,21 @@ match maybeTarget with
         sprintf "Successfully installed in %s" fsxInstallationDir.FullName
     )
 
+match maybeTarget with
+
+| None
+| Some "all" -> MakeAll() |> ignore
+
+| Some "release" ->
+    let buildConfig = BinaryConfig.Release
+    JustBuild buildConfig
+
+| Some "reinstall" ->
+    Install true
+
+| Some "install" ->
+    Install false
+
 | Some "check" ->
 
     // FIXME: contributor should be able to run 'make check' before 'make install'