common.mk: sizes.c for nmake

* common.mk (sizes.c): needs VPATH to outplace build with nmake.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42854 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
win32.c: clock_getres

* win32/win32.c (clock_getres): required as well as clock_gettime().
  [ruby-dev:47699] [Bug #8869]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42855 b2dd03c8-39d4-4d8f-98ff-823fe69b080e