delete obsolete macros (mrb_basic + mrb_object)

correctly validate symbol length

Over a year ago is not "soon" anymore. See:
88483fad
24366930

The comment didn't say why the length is reserved.
Using RITE_LV_NULL_MARK makes things a bit clearer.

This also fixes an off-by-one in mrb_check_intern().

Remove unused macro.

OutOfRange() is no longer used.

Fix error handlings for fprintf() and fputs() to file.

Unify and rename duplicated functions (noregexp() and regexp_check()).

Add prefix(mrb) to noregexp() and regexp_check().

add write barrier to env on pop call info poped. #2525

Add a missing space after ",".

Remove discareded NULL checks and use mrb_malloc() instead of mrb_realloc().

remove unused MSVC strtoll fallback

printf: cast variables to the expected type

use MRB_STRINGIZE

It's defined in mruby/version.h which gets included in mruby.h, so it's
safe to use.

%x expects unsigned int and %p expects void *

GCC emits a diagnostic about %p/void* in pedantic mode:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26542

Remove spaces in end-of-line.

Fix and add test for Numeric#pow behavior.