Fix the Windows build.
Fix the Windows build.

* build.conf (libsvn_subr):  Export svn_debug.h.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@880000 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion