sqlite-regex Benchmarks

Caveat: Benchmarks are hard and easy to game

This benchmark isn't exhaustive, and only benchmarks between other widely-used SQLite regex extensions.

REGEXP() across all SQLite regex extensions

Explaination: Essentially running select count(*) from corpus where line regexp "\d{4}-\d{2}-\d{2}", though regexp and sqlean/re doesn't support \d or {4} syntax.

gcc -O3 -shared -fPIC regexp.c -o regexp.dylib

gcc -O3 -shared -fPIC -I./ re.c sqlite3-re.c -o re.dylib