Log Message:
Update to 5.0.1

Changelog:
Changes from 5.0.0 to 5.0.1
---------------------------

1. A number of ChangeLog.1 files that were left out of the distribution
   have been restored.

2. Multiple syntax errors should no longer be able to cause a core dump.

3. Sandbox mode now disallows assigning new filename values in ARGV that
   were not there when gawk was invoked.

4. There are many small documentation improvements in the manual.

5. The new argument "no-ext" to --lint disables ``XXX is a gawk extension''
   lint warnings.

6. Infrastructure upgrades: Bison 3.4.

N. A number of bugs, some of them quite significant, have been fixed.
   See the ChangeLog for details.