LO builds GLib, gdk-pixbuf and Pango using their ancient nmake-based
build mechanisms (that use the make.msc from GLib's build/win32
directory). This compiles against the debugging runtime (the -MDd
switch, msvcr90d.dll) if there is a DEBUG environment variable. We
don't want that. None of LO's own DLLs should use the debugging
runtime even in an --enable-debug build, and the debugging runtime
doesn't get included in the installer.

Change-Id: I04d2dcc0d5bb245af4afac976b6c1fecbf2095e1