Fix build.

src/Main/Base/Project/Src/Project/Solution/Solution.cs

@@ -1211,7 +1211,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			propertyDict["SolutionDir"] = EnsureBackslash(this.Directory);
 			propertyDict["SolutionExt"] = ".sln";
 			propertyDict["SolutionFileName"] = Path.GetFileName(this.FileName);
-			propertyDict["SolutionName"] = this.Name;
+			propertyDict["SolutionName"] = this.Name ?? string.Empty;
 			propertyDict["SolutionPath"] = this.FileName;
 		}
 		

src/Main/Base/Test/MemberLookupHelperTests.cs

@@ -183,6 +183,8 @@ namespace ICSharpCode.SharpDevelop.Tests
 		[Test]
 		public void GetTypeInheritanceTreeOfClassDerivingFromListOfString()
 		{
+			if (DotnetDetection.IsDotnet45Installed())
+				Assert.Ignore(".NET 4.5 adds IReadOnlyList");
 			List<string> results = new List<IReturnType>(
 				MemberLookupHelper.GetTypeInheritanceTree(CreateClassDerivingFromListOfString().DefaultReturnType)
 			).ConvertAll<string>(delegate (IReturnType rt) { return rt.DotNetName; });