Use CMAKE_COMMAND variable instead of hard coded cmake executable name for better portability.

git-svn-id: https://tigervnc.svn.sourceforge.net/svnroot/tigervnc@5088 3789f03b-4d11-0410-bbf8-ca57d06f2519
Fix incorrect dll location in windows setup file template

git-svn-id: https://tigervnc.svn.sourceforge.net/svnroot/tigervnc@5089 3789f03b-4d11-0410-bbf8-ca57d06f2519