build: handle special case of empty namespace better

lib/node_modules/@stdlib/_tools/scripts/create_namespace_types.js

@@ -100,7 +100,7 @@ function createTestFile() {
 * @returns {string} `index.d.ts` contents
 */
 function createDefinitionFile( ns, imports, properties, description ) {
-	return [
+	var lines = [
 		'/*',
 		'* @license Apache-2.0',
 		'*',
@@ -121,16 +121,23 @@ function createDefinitionFile( ns, imports, properties, description ) {
 		'',
 		'// TypeScript Version: 4.1',
 		'',
-		'/* eslint-disable max-lines */',
-		'',
-		imports.join( '\n' ),
-		'',
+		'/* eslint-disable max-lines' + ( ( properties.length === 0 ) ? ', @typescript-eslint/no-empty-interface' : '' ) + ' */',
+		''
+	];
+	if ( imports.length > 0 ) {
+		lines.push( '', imports.join( '\n' ), '' );
+	}
+	lines = lines.concat([
 		'/**',
 		'* Interface describing the `'+ns+'` namespace.',
-		'*/',
-		'interface Namespace {',
-		properties.join( '\n' ),
-		'}',
+		'*/'
+	]);
+	if ( properties.length > 0 ) {
+		lines.push( 'interface Namespace {', properties.join( '\n' ), '}' );
+	} else {
+		lines.push( 'interface Namespace {}' );
+	}
+	lines = lines.concat([
 		'',
 		'/**',
 		'* '+description,
@@ -142,7 +149,8 @@ function createDefinitionFile( ns, imports, properties, description ) {
 		'',
 		'export = ns;',
 		''
-	].join( '\n' );
+	]);
+	return lines.join( '\n' );
 }
 
 /**