suppress warning of cast and remove unnecessary unary plus
use mrb_string_value_ptr to guarantee str_flags is C string
Merge pull request #12 from take-cheeze/small_fix

Small fixes.
local installation for oniguruma
use tar and curl instead of libarchive and net/http
Merge pull request #13 from take-cheeze/tar_curl

Use tar and curl instead of libarchive and net/http.
Enhancements and fixes for Regexp#split.

This commit has two fixes for Regexp#split:

* When the split expression contains captures, include the captures in the
  output.
* Behave sanely when the split expression matches a zero length string.
Merge pull request #14 from chasonr/master

Enhancements and fixes for Regexp#split.
Need string.h on Windows (mingw64).
Merge pull request #15 from chasonr/master

Need string.h on Windows (mingw64).
Fix #16 Thanks @unak
Disable on windows
Fixed variable type