diff --git a/src/Illuminate/Foundation/Console/TinkerCommand.php b/src/Illuminate/Foundation/Console/TinkerCommand.php
index <HASH>..<HASH> 100755
--- a/src/Illuminate/Foundation/Console/TinkerCommand.php
+++ b/src/Illuminate/Foundation/Console/TinkerCommand.php
@@ -118,7 +118,7 @@ class TinkerCommand extends Command {
 	 */
 	protected function supportsBoris()
 	{
-		return (extension_loaded('readline') and extension_loaded('posix'));
+		return (extension_loaded('readline') and extension_loaded('posix') and extension_loaded('pcntl'));
 	}
 
 }
Changed supportBoris to check for pcntl

Boris also requires the pcntl php extension, so we should check if its there before using Boris for tinkering.