* gdb.base/multi-forks.exp: Use a loop. Allow "fork" as a stopped function name.
* gdb.base/checkpoint.c: New file. * gdb.base/checkpoint.exp: New file. * gdb.base/multi-fork.c: New file. * gdb.base/multi-fork.exp: New file. * gdb.base/pi.txt: New file (data for checkpoint.c test).