Fix #15880: Prevent "stalling" when running dev server in background by ignoring SIGTTOU for the duration of tcsetattr.
Fix #15880: Prevent "stalling" when running dev server in background by ignoring SIGTTOU for the duration of tcsetattr.

git-svn-id: 554f83ef17aa7291f84efa897c1acfc5d0035373@16326 bcc190cf-cafb-0310-a4f2-bffc1f526a37

svn2github/django,svn2github/django,svn2github/django