bug#16232: [PATCH] grep: make --ignore-case (-i) faster (sometimes 10x) in multibyte locales

[Norihiro TANAKA]

Hi Jim,

Your patch is probably right.

However, I think that the true cause for 100x slow is that DFA engine is
slower than regex engine for case-insensitive matching on a non-UTF-8
locle.

On a multibyte locale, for case-insensitive "a" grep prefers DFA engine,
but for character class "[Aa]" prefers regex engine.

Norihiro