class/module body to honor whether value is required or not; reduce a few instructions for normal cases
Change :vattr= to :cattr= in respond_to? test
rename mrb_intern_litral -> mrb_intern_static
zero copy intern from static allocate irep
zero copy str_new from static allocate irep
Merge branch 'master' of github.com:mruby/mruby
clear STR_NOFREE flag on modify
avoid copying when the original string comes with MRB_STR_NOFREE
Merge pull request #1619 from carsonmcdonald/fixmoduleattrtest

Change :vattr= to :cattr= in respond_to? test
wrong operator precedence fixed
Merge branch 'master' into iij