fix off-by-one error in attrsym

The allocation size for null-terminated character is lacking.
In actual, it is no problem in most case
because codegen_palloc allocates more a memory size than required size.
fix indent.
Add mruby-bin-mruby-config
mruby command should not execute program on "syntax only option(-c)".
chmod 755
Don't echo empty string. (Remove workaround for windows)
Merge pull request #1799 from cubicdaiya/issues/off_by_one_error2

fix off-by-one error in attrsym
Merge pull request #1800 from tmash06/fix_indent

fix indent.
Merge pull request #1802 from tmash06/fix_syntax_check_no_exec

mruby command should not execute program on "syntax only option(-c)".
Merge pull request #1801 from mattn/mruby-config

Add mruby-bin-mruby-config
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.
fix mruby command returning EXIT_SUCCESS when program file can't be
opened.