merge revision(s) 43398,43407,43408,43417: [Backport #9044]

	* win32/Makefile.sub (config.h): VC 2013 supports C99 mathematics
	  functions.  [ruby-core:57981] [Bug #9044]

	* include/ruby/win32.h (rb_infinity_float): suppress overflow in
	  constant arithmetic warnings.  [ruby-core:57981] [Bug #9044]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@43648 b2dd03c8-39d4-4d8f-98ff-823fe69b080e