Fix up for gradle build

Author: a-maurice

source/IOSResolver/IOSResolver.csproj

@@ -50,6 +50,7 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Xml" />
+    <Reference Include="System.Xml.Linq" />
     <Reference Include="Google.JarResolver">
       <HintPath>..\AndroidResolver\bin\Release\Google.JarResolver.dll</HintPath>
     </Reference>

source/IOSResolver/src/SwiftPackageManager.cs

@@ -199,7 +199,7 @@ internal static List<RemoteSwiftPackage> Resolve(List<RemoteSwiftPackage> packag
                                                         .Where(rp => !string.IsNullOrEmpty(rp))
                                                         .SelectMany(rp => rp.Split(','))
                                                         .Select(p => p.Trim())
-                                                        .Distinct()),
+                                                        .Distinct().ToArray()),
             RemotePackage = remotePackage
           };
           finalPackages.Add(mergedPackage);