2015-04-23  Sandra Loosemore  <sandra@codesourcery.com>

	gdb/
	* nios2-tdep.c (nios2_get_next_pc): Make non-static.
	* nios2-tdep.h (nios2_get_next_pc): Declare as extern.
	* nios2-linux-tdep.c: Include breakpoint.h.
	(NIOS2_SIGRETURN_TRAMP_ADDR): Define.
	(NIOS2_SIGRETURN_REGSAVE_OFFSET): Define.
	(nios2_linux_rt_sigreturn_init): Adjust base address of
	register save area.
	(nios2_linux_software_single_step): New target hook function.
	(nios2_linux_init_abi): Install it.

	gdb/testsuite/
	* gdb.base/sigaltstack.exp: Add kfails for nios2-*-linux*.
	* gdb.base/sigstep.exp: Likewise.