move TRANSPARENT #define from windows.h out of global namespace

so it doesn't conflict with enums

Change-Id: Ic4143130762d6e878d7c23276393ba09d9f86d45
Reviewed-on: https://gerrit.libreoffice.org/11880
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>