Workaround for Dotenv and Laravel 5.x issues with concurrent requests failing (especially on Windows) because of PHP threaded getenv/putenv implementation. To make this work on Laravel, you will need also https://gist.github.com/progmars/1e545d96dd48676a2aa7 patch.

laravel_5_x_getenv_dotenv_mt_reliability_workaround.patch

This is a workaround patch for `getenv()` unstable behavior in multithreaded "PHP as Apache module" environments 
(e.g. some prepackaged WAMP stacks).
See 
https://github.com/vlucas/phpdotenv/issues/76
https://github.com/vlucas/phpdotenv/issues/163
This fix is intended only for development environments, the same as Dotenv itself.
In production, you should use Laravel's `config:cache` command to avoid `env` helper and Dotenv altogether.
The paths are based on Composer's vendor directory. 
diff --git a/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/DetectEnvironment.php b/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/DetectEnvironment.php
index 673ce3a..f250729 100644
--- a/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/DetectEnvironment.php
+++ b/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/DetectEnvironment.php
@@ -17,11 +17,18 @@ class DetectEnvironment
     public function bootstrap(Application $app)
     {
         if (! $app->configurationIsCached()) {
+            // Patched to support more reliable environment value lookup
+            // in some environments.
+            // See
+            // https://github.com/vlucas/phpdotenv/issues/76
+            // https://github.com/vlucas/phpdotenv/issues/163
+            $dotenv = new Dotenv($app->environmentPath(), $app->environmentFile());
             try {
-                (new Dotenv($app->environmentPath(), $app->environmentFile()))->load();
+                $dotenv->load();
             } catch (InvalidPathException $e) {
                 //
             }
+            $app->instance('dotenv.loader', $dotenv->getLoader());
         }
     }
 }
diff --git a/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php b/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php
index 05541f7..65905fd 100644
--- a/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php
+++ b/vendor/laravel/framework/src/Illuminate/Foundation/helpers.php
@@ -330,9 +330,15 @@ if (! function_exists('env')) {
      */
     function env($key, $default = null)
     {
-        $value = getenv($key);
-
-        if ($value === false) {
+        // Patched to support more reliable environment value lookup
+        // in some environments.
+        // See
+        // https://github.com/vlucas/phpdotenv/issues/76
+        // https://github.com/vlucas/phpdotenv/issues/163
+        $value = app('dotenv.loader')->getEnvironmentVariable($key);
+
+        // Changed to `null` for getEnvironmentVariable() result check.
+        if ($value === null) {
             return value($default);
         }