* tracepoint.c: Include gdbcore.h.
(tfile_xfer_partial): Return partial results, also try reading
from executable.
(tfile_has_all_memory): New function.
(init_tfile_ops): Use it.
* gdb.trace/tfile.c: Add a variable split across two blocks, and a
constant global.
* gdb.trace/tfile.exp: Try to print them.