its own copy of GetTimeInMillis().
+ This allows us to get rid of multiple versions of GetTimeInMillis().
It is provided by libos.a if DDXTIME is undefined.
XXX macppc may be a special case since it builds both XFree86 and Xmacppc
will resolve later if found to be an issue.
submitted by David P. Reese Jr. in PR xsrc/23968, updated for the recent
changes that have been made in "src/x11". (This currently builds and runs,
unlike the native XF4 mac68k xsrc build.)
