Prevent segfault when editing a textarea field with vi

add fix for segfault that can occur when editing a textarea field
with vi, and returning to w3m (it seems to happen if the terminal
is not writable, as when using w3m after 'su - some_user')

Origin: https://build.opensuse.org/package/view_file/openSUSE:Factory/w3m/w3m-0.4.1-textarea-segfault.dif?expand=1
Merge branch 'bug/textarea-segfault'
Fix a few harmless uninitialized variables

Origin: https://build.opensuse.org/package/view_file/openSUSE:Factory/w3m/w3m-uninitialized.patch?expand=1
Merge branch 'bug/uninitialized'
Change the default to alt_entity=0

change the default for the option "Use ASCII equivalents to
display entities" from YES to NO.

Origin: https://build.opensuse.org/package/view_file/openSUSE:Factory/w3m/w3m-0.5.1-no-ASCII-equivalents-by-default.patch?expand=1
Bug-Novell: https://bugzilla.novell.com/show_bug.cgi?id=247397
Merge branch 'bug/no-ascii-default'
Fix crash in parse_tag() during every start

Origin: https://build.opensuse.org/package/view_file/openSUSE:Factory/w3m/w3m-parsetagx-crash.patch?expand=1
Merge branch 'bug/parsetagx-crash'