* win32/README.win32: `make up` is only necessary when building from SVN source.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62843 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

win32/README.win32

@@ -45,7 +45,7 @@
     And add ((|RUBYW_INSTALL_NAME|)) to change the name of the
     executable without console window if also you want.
 
-(3) Run `((%nmake up%))'
+(3) Run `((%nmake up%))' if you are building from SVN source.
 
 (4) Run `((%nmake%))'