[Security] Fix not being able to change the authorization prompt (#3612)

When asking for user credentials it was not possible to change the
default authorization prompt message so the application name is used
by default. When running an application with Mono this will be
mono-sgen64 or mono-sgen32.

The prompt is now added to the environment authorization item set
passed to AuthorizationCreate. It was being passed as part of the
rights item set. This allows a custom message to be set in the
authorization dialog.

src/Security/Authorization.cs

@@ -172,17 +172,16 @@ namespace Security {
 				unsafe {
 					if (parameters != null){
 						ppars = &pars;
-						pars.ptrToAuthorization = (AuthorizationItem *) Marshal.AllocHGlobal (sizeof (AuthorizationItem) * 3);
+						pars.ptrToAuthorization = (AuthorizationItem *) Marshal.AllocHGlobal (sizeof (AuthorizationItem) * 2);
 						if (parameters.PathToSystemPrivilegeTool != null)
 							EncodeString (ref pars.ptrToAuthorization [pars.count++], "system.privilege.admin", parameters.PathToSystemPrivilegeTool);
-						if (parameters.Prompt != null)
-							EncodeString (ref pars.ptrToAuthorization [pars.count++], "prompt", parameters.Prompt);
 						if (parameters.IconPath != null)
 							EncodeString (ref pars.ptrToAuthorization [pars.count++], "prompt", parameters.IconPath);
 					}
-					if (environment != null){
+					if (environment != null || (parameters != null && parameters.Prompt != null)){
 						penv = &env;
-						env.ptrToAuthorization = (AuthorizationItem *) Marshal.AllocHGlobal (sizeof (AuthorizationItem) * 3);
+						env.ptrToAuthorization = (AuthorizationItem *) Marshal.AllocHGlobal (sizeof (AuthorizationItem) * 4);
+						if (environment != null){
 							if (environment.Username != null)
 								EncodeString (ref env.ptrToAuthorization [env.count++], "username", environment.Username);
 							if (environment.Password != null)
@@ -190,6 +189,11 @@ namespace Security {
 							if (environment.AddToSharedCredentialPool)
 								EncodeString (ref env.ptrToAuthorization [env.count++], "shared", null);
 						}
+						if (parameters != null){
+							if (parameters.Prompt != null)
+								EncodeString (ref env.ptrToAuthorization [env.count++], "prompt", parameters.Prompt);
+						}
+					}
 					code = AuthorizationCreate (ppars, penv, flags, out auth);
 					if (code != 0)
 						return null;