* configure.in: do not use buggy tgamma() of mingw.
* missing/tgamma.c (tgamma): merge fix for inifity from
ruby_tgamma. since msvcr120.dll and later have tgamma, this
implementation will not be used.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58691 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
(math_lgamma): new method Math.lgamma.
* include/ruby/missing.h (tgamma): declared unless HAVE_TGAMMA.
(lgamma_r): declared unless HAVE_LGAMMA_R.
* configure.in (tgamma): check for replacement funtions.
(lgamma_r): ditto.
* missing/tgamma.c: new file. based on gamma.c from
"C-gengo niyoru saishin algorithm jiten" (New Algorithm handbook
in C language) (Gijyutsu hyouron sha, Tokyo, 1991)
by Haruhiko Okumura.
* missing/lgamma_r.c: ditto.
* LEGAL (missing/tgamma.c): describe as public domain.
(missing/lgamma_r.c): ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@15388 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
