gem の sqlite3-ruby をインストールしようとしたらエラー
$ gem install sqlite3-ruby WARNING: Installing to ~/.gem since /usr/lib/ruby/gems/1.8 and /usr/bin aren't both writable. WARNING: You don't have /home/hira/.gem/ruby/1.8/bin in your PATH, gem executables will not run. Building native extensions. This could take a while... ERROR: Error installing sqlite3-ruby: ERROR: Failed to build gem native extension. /usr/bin/ruby extconf.rb checking for fdatasync() in -lrt... yes checking for sqlite3.h... no make make: *** `sqlite3_api_wrap.o' に必要なターゲット `ruby.h' を make するルールがありません. 中止.
sqlite, sqlite-devel がないので、CentOS なら、
# yum install sqlite sqlite-devel
これで大丈夫。