Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC: r257315, r260445, r264803

Update byacc to 20140422

Merge byacc 20130925

2 changes:
- Increase default stack-size so that used to be our default stack-size prior byacc import
- fix two loop-limits found by clang 3.3

Import byacc version 20130925