fix incorrect integer-overflow checkups in OP_SUB/OP_SUBI case.
Merge pull request #625 from skandhas/pr-fix-integer-overflow-checkups-in-OP_SUB-OP_SUBI

fix incorrect integer-overflow checkups in OP_SUB/OP_SUBI case.
fgetc(3) returns int.

Note: "char" is actually "unsigned char" on some platforms including
NetBSD/arm.  Comparing char value with EOF(-1) always fails on the
platforms.
rebuild binaries when mrbgem archives are updated.
add mrb_closure_new_cfunc to header
Merge pull request #626 from iij/pr-generator-eof-check

generator dumps core on NetBSD/arm
Merge pull request #630 from mrbrdo/master

mrb_closure_new_cfunc proc.h
Merge pull request #627 from iij/pr-mrbgems-dependency

rebuild binaries when mrbgem archives are updated.
Moved some building script from GNU make to Ruby script
Added minirake what's Rake subset
Merge branch 'master' into use_ruby_for_building
Fix a typo in comment

elment ->
element
MSVC doesn't define strtoll but _strtoi64.
Moved some building script from GNU make to Ruby script
Added minirake what's Rake subset
Merge pull request #631 from darashi/fix-typo

Fix a typo in comment
Merge pull request #632 from cremno/msvc-strtoll

MSVC doesn't define strtoll
should not ignore exception on top-level; close #635
nextc() might have problem on bytes higer than 0x80; close #628
Merge pull request #634 from masuidrive/use_ruby_for_building

Use CRuby for building
fix (-T, --tasks) show tasks
Merge pull request #636 from selman/minirake_tasks

fix (-T, --tasks) show tasks