disable url based features

Author: barak007

lib/input.js

@@ -130,7 +130,9 @@ class Input {
 
     result.input = { line, column, source: this.css }
     if (this.file) {
-      result.input.url = pathToFileURL(this.file).toString()
+      if(pathToFileURL) {
+        result.input.url = pathToFileURL(this.file).toString()
+      }
       result.input.file = this.file
     }
 
@@ -162,7 +164,11 @@ class Input {
     }
 
     if (fromUrl.protocol === 'file:') {
-      result.file = fileURLToPath(fromUrl)
+      if(fileURLToPath){
+        result.file = fileURLToPath(fromUrl)
+      } else {
+        throw new Error(`file: protocol is not available in this postcss build`);
+      }
     }
 
     let source = consumer.sourceContentFor(from.source)

lib/map-generator.js

@@ -4,7 +4,7 @@ let { dirname, resolve, relative, sep } = require('path')
 let { pathToFileURL } = require('url')
 let mozilla = require('source-map')
 
-let pathAvailable = Boolean(dirname, resolve, relative, sep)
+let pathAvailable = Boolean(dirname && resolve && relative && sep)
 
 class MapGenerator {
   constructor(stringify, root, opts) {