Error installing sqlite3

It seems that I can't install sqlite3 after installing blunder. The ruby version is:

$ ruby -v ruby 2.1.7p400 (2015-08-18 revision 51632) [x64-mingw32]

when i run this command, this log appears:

$ gem install sqlite3 ERROR: Error installing sqlite3: ERROR: Failed to build gem native extension.

C:/Ruby21-x64/bin/ruby.exe extconf.rb

checking for sqlite3.h... no sqlite3.h is missing. Install SQLite3 from http://www.sqlite.org/ first. *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options.

Provided configuration options: --with-opt-dir --without-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=C:/Ruby21-x64/bin/ruby --with-sqlite3-dir --without-sqlite3-dir --with-sqlite3-include --without-sqlite3-include=${sqlite3-dir}/include --with-sqlite3-lib --without-sqlite3-lib=${sqlite3-dir}/lib

extconf failed, exit code 1

Gem files will remain installed in C:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/sqlite3-1.3.11 for inspection. Results logged to C:/Ruby21-x64/lib/ruby/gems/2.1.0/extensions/x64-mingw32/2.1.0/sqlite3-1.3.11/gem_make.out Temporarily enhancing PATH to include DevKit... Building native extensions. This could take a while...

What should i do now?