a7ae1dc has broken the windows builds

I've attached a small patch which should get the windows builds up and
running again.

They're currently failing from this:

"c:\prog\bf\root\HEAD\pgsql.build\pgsql.sln" (default target) (1) ->
"c:\prog\bf\root\HEAD\pgsql.build\pg_upgrade_support.vcxproj" (default
target) (67) ->
(Link target) ->
pg_upgrade_support.obj : error LNK2001: unresolved external symbol
IsBinaryUpgrade
[c:\prog\bf\root\HEAD\pgsql.build\pg_upgrade_support.vcxproj]
.\Release\pg_upgrade_support\pg_upgrade_support.dll : fatal error
LNK1120: 1 unresolved externals
[c:\prog\bf\root\HEAD\pgsql.build\pg_upgrade_support.vcxproj]

0 Warning(s)
2 Error(s)

Regards

David Rowley