clang-analyzer: Fix dead assignments in window.c.
clang-analyzer: Fix dead assignments in message.c.
clang-analyzer: Fix dead assignments in spell.c.
clang-analyzer: Fix dead assignments in regexp_nfa.c.
clang-analyzer: Fix dead assignments in screen.c.
clang-analyzer: Fix dead assignments in search.c.
clang-analyzer: Fix dead assignments in arabic.c.
clang-analyzer: Fix dead assignments in option.c.
clang-analyzer: Fix dead assignments in syntax.c.