s/\\"/"/g in mruby-config
Fix #1803
add existing include/ directory only
Merge pull request #1804 from mattn/fix-quote

Fix #1803
Merge pull request #1805 from take-cheeze/existing_include

Add existing include/ directory only.
should check crossing C boudary from resume
Merge branch 'master' of github.com:mruby/mruby
fix argument spec setting of Kernel.exit method.
this method requires 1 optional argument.
Merge pull request #1806 from tmash06/fix_exit_method_aspec_setting

fix argument spec setting of Kernel.exit method.