* gdb.t16/printcmd.exp: Don't print variables before running program.

	* gdb.t16/printcmd.exp: Don't print variables before running program.

	* gdb.t06/break.exp: Don't require envp argument to main.

	* gdb.t0{2,3,4,5}/gdbme.c [_AIX]: Use signed keyword.

	* gdb.t02/whatis.exp, gdb.t11/list.exp:
	Add xfails for rs6000.

	* gdb.t02/whatis.exp: Re-write other tests
	not to re-test something we already tested.

	* gdb.t{03,15,16}/gdbme.c: Reference all variables and make sure
	each type used has a variable of that type.