Build fixes and a little more juggling

Support/Sources/COM/COMError+createErrorInfo.swift

@@ -0,0 +1,23 @@
+import COM_ABI
+
+extension COMError {
+    /// Creates an instance of `ICreateErrorInfo`.
+    public static func createErrorInfo() throws -> ICreateErrorInfo {
+        var createErrorInfo = ICreateErrorInfoProjection.abiDefaultValue
+        defer { ICreateErrorInfoProjection.release(&createErrorInfo) }
+        try COMError.fromABI(SWRT_CreateErrorInfo(&createErrorInfo))
+        return try NullResult.unwrap(ICreateErrorInfoProjection.toSwift(createErrorInfo))
+    }
+
+    /// Creates an instance of `IErrorInfo` with prepopulated fields.
+    public static func createErrorInfo(guid: GUID? = nil, source: String? = nil, description: String?,
+            helpFile: String? = nil, helpContext: UInt32? = nil) throws -> IErrorInfo {
+        let errorInfo = try createErrorInfo()
+        if let guid { try errorInfo.setGUID(guid) }
+        if let source { try errorInfo.setSource(source) }
+        if let description { try errorInfo.setDescription(description) }
+        if let helpFile { try errorInfo.setHelpFile(helpFile) }
+        if let helpContext { try errorInfo.setHelpContext(helpContext) }
+        return try errorInfo.queryInterface(IErrorInfoProjection.self)
+    }
+}

Support/Sources/COM/COMError.swift

@@ -38,7 +38,7 @@ public struct COMError: COMErrorProtocol, CustomStringConvertible {
     }
 
     public init(hresult: HResult, description: String?) {
-        self.init(hresult: hresult, errorInfo: description.flatMap { try? createErrorInfo(description: $0) })
+        self.init(hresult: hresult, errorInfo: description.flatMap { try? Self.createErrorInfo(description: $0) })
     }
 
     public var description: String {

Support/Sources/WindowsRuntime/ProjectedTypes/IRestrictedErrorInfo.swift

@@ -41,10 +41,10 @@ public enum IRestrictedErrorInfoProjection: COMProjection {
 
     private final class Import: COMImport<IRestrictedErrorInfoProjection>, IRestrictedErrorInfoProtocol {
         func getErrorDetails(
-                description: inout String?,
-                error: inout HResult,
-                restrictedDescription: inout String?,
-                capabilitySid: inout String?) throws {
+                _ description: inout String?,
+                _ error: inout HResult,
+                _ restrictedDescription: inout String?,
+                _ capabilitySid: inout String?) throws {
             try _interop.getErrorDetails(&description, &error, &restrictedDescription, &capabilitySid)
         }