Remove obsolete custom platform detection.

Duplicati.Library.RestAPI/RESTMethods/Filesystem.cs

@@ -72,7 +72,7 @@ namespace Duplicati.Server.WebServer.RESTMethods
 
             path = SpecialFolders.ExpandEnvironmentVariables(path);
 
-            if (Platform.IsClientPosix && !path.StartsWith("/", StringComparison.Ordinal))
+            if ((OperatingSystem.IsMacOS() || OperatingSystem.IsLinux()) && !path.StartsWith("/", StringComparison.Ordinal))
             {
                 info.ReportClientError("The path parameter must start with a forward-slash", System.Net.HttpStatusCode.BadRequest);
                 return;
@@ -111,7 +111,7 @@ namespace Duplicati.Server.WebServer.RESTMethods
 
                 IEnumerable<Serializable.TreeNode> res;
 
-                if (!Platform.IsClientPosix && (path.Equals("/") || path.Equals("")))
+                if (!(OperatingSystem.IsMacOS() || OperatingSystem.IsLinux()) && (path.Equals("/") || path.Equals("")))
                 {
                     res = DriveInfo.GetDrives()
                             .Where(di =>

Duplicati.Library.RestAPI/RESTMethods/Licenses.cs

@@ -29,7 +29,7 @@ namespace Duplicati.Server.WebServer.RESTMethods
         {
             var exefolder = System.IO.Path.GetDirectoryName(Duplicati.Library.Utility.Utility.getEntryAssembly().Location);
             var path = System.IO.Path.Combine(exefolder, "licenses");
-            if (Duplicati.Library.Common.Platform.IsClientOSX && !Directory.Exists(path))
+            if (OperatingSystem.IsMacOS() && !Directory.Exists(path))
             {
                 // Go up one, as the licenses cannot be in the binary folder in MacOS Packages
                 exefolder = Path.GetDirectoryName(exefolder);

Duplicati.Library.RestAPI/RESTMethods/SystemInfo.cs

@@ -71,7 +71,7 @@ namespace Duplicati.Server.WebServer.RESTMethods
                 DefaultUpdateChannel = Duplicati.Library.AutoUpdater.AutoUpdateSettings.DefaultUpdateChannel,
                 DefaultUsageReportLevel = Duplicati.Library.UsageReporter.Reporter.DefaultReportLevel,
                 ServerTime = DateTime.Now,
-                OSType = Platform.IsClientPosix ? (Platform.IsClientOSX ? "OSX" : "Linux") : "Windows",
+                OSType = OperatingSystem.IsWindows() ? "Windows" : (OperatingSystem.IsMacOS() ? "OSX" : "Linux"),
                 DirectorySeparator = System.IO.Path.DirectorySeparatorChar,
                 PathSeparator = System.IO.Path.PathSeparator,
                 CaseSensitiveFilesystem = Duplicati.Library.Utility.Utility.IsFSCaseSensitive,