Bug fix in regex.
Merge branch 'gawk-4.1-stable'
Fixes in helpers/testdfa.c.
Merge branch 'gawk-4.1-stable'
Update to automake 1.13.4 and libtool 2.4.2.418.
Update NEWS.
Merge branch 'gawk-4.1-stable'
Make extensions controlled by configure time option.
Merge branch 'gawk-4.1-stable'