Don't break when options._flags is undefined entirely

src/phase-streams/dedupe-bundle-css.js

@@ -18,7 +18,7 @@ module.exports = function (state) {
 		let allCss = "";
 		let loaderItem;
 	
-		let entryPoint = (options._flags.entries != null)
+		let entryPoint = (options._flags != null && options._flags.entries != null)
 			// Get the (absolute!) path of the folder containing the initial entry file, as a reference point for relative paths in the output
 			? path.dirname(path.resolve(options._flags.entries[0]))
 			// ... or, if no entry file is specified, go off the current working directory
@@ -27,13 +27,13 @@ module.exports = function (state) {
 		return stream((item) => {
 			// And the same for the loader shim path. All this relative-path stuff is to prevent absolute filesystem URLs from leaking into the output, as those might contain sensitive information.
 			let relativeLoaderPath = path.relative(path.dirname(item.file), loaderShimPath);
-	
+
 			if (isCss(item)) {
 				return Promise.try(() => {
 					return processFile(item);
 				}).then(({ result, icssExports }) => {
 					allCss += `/* from ${path.relative(entryPoint, item.file)} */\n\n${result.css}\n\n`;
-	
+
 					if (!item.__icssify__discardable) {
 						return {
 							... item,
@@ -56,6 +56,7 @@ module.exports = function (state) {
 						source: loaderItem.source.replace('"## CONTENT MARKER ##"', JSON.stringify(allCss))
 					};
 				} else {
+					// FIXME: Can occur if some dependency also gets processed and require()s a CSS file, but does not specify icssify as a transform (but the using project does) -- like with ui-lib + site-builder
 					throw new Error("Processed CSS, but global loader was not encountered. This should never happen, please report it as a bug!");
 				}
 			}