ext/bigdecimal/extconf.rb, ext/bigdecimal/bigdecimal.h (labs, llabs): support environments missing labs and llabs.
ext/bigdecimal/bigdecimal.h (vabs): added.
ext/bigdecimal/extconf.rb, ext/bigdecimal/bigdecimal.h, ext/bigdecimal/bigdecimal.c, test/bigdecimal/test_bigdecimal.rb (TestBigDecimal#test_new): replace U_LONG, S_LONG, S_INT, and U_INT with appropreate standard or ruby-provided types.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@28992 b2dd03c8-39d4-4d8f-98ff-823fe69b080e