Workaround for VC 19.42.34433 again

Prefix underscore is already removed here.

Author: nobu

win32/mkexports.rb

@@ -122,7 +122,7 @@ def each_export(objs)
           elsif !l.sub!(/^(\S+) \([^@?\`\']*\)$/, '\1')
             next
           end
-          next if /\A__+ucrt_/ =~ l
+          next if /\A_?ucrt_/ =~ l
         when /DLL/
           next unless l.sub!(/^\s*\d+\s+[[:xdigit:]]+\s+[[:xdigit:]]+\s+/, '')
         else