Restore check on ATOM_HOME

(undo db57479bf9)
Check on ATOM_HOME is not superfluous - needed on Linux because of
difference in inheriting environment variables between browser and render
processes

static/index.js

@@ -13,6 +13,11 @@
         console.error('Unhandled promise rejection %o with error: %o', promise, error)
       })
 
+      // Ensure ATOM_HOME is always set before anything else is required
+      // This is because of a difference in Linux not inherited between browser and render processes
+      // issue #5142
+      setupAtomHome()
+
       // Normalize to make sure drive letter case is consistent on Windows
       process.resourcesPath = path.normalize(process.resourcesPath)
 
@@ -77,6 +82,24 @@
     require('ipc').sendChannel('window-command', 'window:loaded')
   }
 
+  function setupAtomHome () {
+    if (!process.env.ATOM_HOME) {
+      var home
+      if (process.platform === 'win32') {
+        home = process.env.USERPROFILE
+      } else {
+        home = process.env.HOME
+      }
+      var atomHome = path.join(home, '.atom')
+      try {
+        atomHome = fs.realpathSync(atomHome)
+      } catch (error) {
+        // Ignore since the path might just not exist yet.
+      }
+      process.env.ATOM_HOME = atomHome
+    }
+  }
+
   function setupCsonCache (cacheDir) {
     require('season').setCacheDir(path.join(cacheDir, 'cson'))
   }