--- a/Default/exec.py
+++ b/Default/exec.py
@@ -76,6 +76,7 @@
                 stdin=subprocess.PIPE,
                 startupinfo=startupinfo,
                 env=proc_env,
+                preexec_fn=os.setsid,
                 shell=False)
         elif shell_cmd and sys.platform == "linux":
             # Explicitly use /bin/bash on Linux, to keep Linux and OSX as
@@ -88,6 +89,7 @@
                 stdin=subprocess.PIPE,
                 startupinfo=startupinfo,
                 env=proc_env,
+                preexec_fn=os.setsid,
                 shell=False)
         else:
             # Old style build system, just do what it asks
@@ -98,6 +100,7 @@
                 stdin=subprocess.PIPE,
                 startupinfo=startupinfo,
                 env=proc_env,
+                preexec_fn=os.setsid,
                 shell=shell)

         if path:
@@ -111,7 +114,6 @@

     def kill(self):
         if not self.killed:
-            self.killed = True
             if sys.platform == "win32":
                 # terminate would not kill process opened by the shell cmd.exe,
                 # it will only kill cmd.exe leaving the child running
@@ -121,7 +123,9 @@
                     "taskkill /PID " + str(self.proc.pid),
                     startupinfo=startupinfo)
             else:
+                os.killpg(self.proc.pid, signal.SIGTERM)
                 self.proc.terminate()
+            self.killed = True
             self.listener = None

     def poll(self):