rb_num_t happen to be unsigned; introduce signed variant

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61728 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2018-01-09 13:30:27 +00:00 · 2018-01-09 13:30:27 +00:00 · df76e35333
--- a/vm_core.h
+++ b/vm_core.h
@ -136,6 +136,7 @@
 #endif /* OPT_CALL_THREADED_CODE */

 typedef unsigned long rb_num_t;
+typedef   signed long rb_snum_t;

 enum ruby_tag_type {
    RUBY_TAG_NONE	= 0x0,