Merge {i386,amd64}_linux_read_description

This commit merges i386_ and amd64_linux_read_description, renaming
both to x86_linux_read_description.

gdb/
2014-06-27  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c (amd64_linux_read_description): Renamed to
	x86_linux_read_description.  All uses updated.  amd64-specific
	code conditionalized.  Conditionalized i386-specific code added.
	Redundant cast removed.
	* i386-linux-nat.c (i386_linux_read_description): Renamed to
	x86_linux_read_description.  All uses updated.  i386-specific
	code conditionalized.  Conditionalized amd64-specific code added.
	One sizeof replaced with the actual type it is describing.
Merge ps_get_thread_area

This commit adds a new helper, x86_linux_get_thread_area, to
hold the common parts of the ps_get_thread_area functions in
i386-linux-nat.c and amd64-linux-nat.c.

gdb/
2014-06-27  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c (x86_linux_get_thread_area): New function.
	(ps_get_thread_area): Delegate to the above in 32-bit mode.
	* i386-linux-nat.c (x86_linux_get_thread_area): New function.
	(ps_get_thread_area): Delegate to the above.
Pull out common parts of _initialize_{i386,amd64}_linux_nat

This commit adds two new helpers, x86_linux_create_target
and x86_linux_register_target, to hold the parts of
_initialize_i386_linux_nat and _initialize_amd64_linux_nat
which are common.

gdb/
2014-06-27  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c (x86_linux_create_target): New function.
	(x86_linux_register_target): Likewise.
	(_initialize_amd64_linux_nat): Delegate to the above new functions.
	* i386-linux-nat.c (x86_linux_create_target): New function.
	(x86_linux_register_target): Likewise.
	(_initialize_i386_linux_nat): Delegate to the above new functions.
Comment and whitespace changes

This commit merges the comments and whitespace in the common
parts of i386-linux-nat.c and amd64-linux-nat.c.

gdb/
2014-06-27  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c: Comment and whitespace changes.
	* i386-linux-nat.c: Comment and whitespace changes.
Move duplicated code into new files

This commit moves the shared code in {i386,amd64}-linux-nat.c
into the new files x86-linux-nat.[ch].  Additionally, a new
file i386-linux-nat.h was required to expose a value required
by the 32-bit code in x86-linux-nat.c.

gdb/
2014-06-27  Gary Benson  <gbenson@redhat.com>

	* i386-linux-nat.h: New file.
	* x86-linux-nat.h: Likewise.
	* x86-linux-nat.c: Likewise.
	* Makefile.in (HFILES_NO_SRCDIR): Add the above new headers.
	* config/i386/linux.mh (NATDEPFILES): Add x86-linux-nat.o.
	* config/i386/linux64.mh (NATDEPFILES): Likewise.
	* amd64-linux-nat.c (x86-linux-nat.h): New include.
	(PTRACE_GETREGSET): Now in x86-linux-nat.h.
	(PTRACE_SETREGSET): Likewise.
	(arch_lwp_info): Now in x86-linux-nat.c.
	(have_ptrace_getregset): Now in x86-linux-nat.h.
	(x86_linux_dr_get): Now in x86-linux-nat.c.
	(x86_linux_dr_set): Likewise.
	(x86_linux_dr_get_addr): Likewise.
	(x86_linux_dr_get_control) Likewise.:
	(x86_linux_dr_get_status): Likewise.
	(update_debug_registers_callback): Likewise.
	(x86_linux_dr_set_control): Likewise.
	(x86_linux_dr_set_addr): Likewise.
	(x86_linux_prepare_to_resume): Likewise.
	(x86_linux_new_thread): Likewise.
	(x86_linux_new_fork): Likewise.
	(x86_linux_get_thread_area): Likewise.
	(super_post_startup_inferior): Likewise.
	(x86_linux_child_post_startup_inferior): Likewise.
	(AMD64_LINUX_USER64_CS): Likewise.
	(AMD64_LINUX_X32_DS): Likewise.
	(x86_linux_read_description): Likewise.
	(x86_linux_enable_btrace): Likewise.
	(x86_linux_disable_btrace): Likewise.
	(x86_linux_teardown_btrace): Likewise.
	(x86_linux_read_btrace): Likewise.
	(x86_linux_create_target): Likewise.
	(x86_linux_register_target): Likewise.
	* i386-linux-nat.c (x86-linux-nat.h): New include.
	(PTRACE_GETREGSET): Now in x86-linux-nat.h.
	(PTRACE_SETREGSET): Likewise.
	(arch_lwp_info): Now in x86-linux-nat.c.
	(have_ptrace_getregset): Now in x86-linux-nat.h.
	(x86_linux_dr_get): Now in x86-linux-nat.c.
	(x86_linux_dr_set): Likewise.
	(x86_linux_dr_get_addr): Likewise.
	(x86_linux_dr_get_control) Likewise.:
	(x86_linux_dr_get_status): Likewise.
	(update_debug_registers_callback): Likewise.
	(x86_linux_dr_set_control): Likewise.
	(x86_linux_dr_set_addr): Likewise.
	(x86_linux_prepare_to_resume): Likewise.
	(x86_linux_new_thread): Likewise.
	(x86_linux_new_fork): Likewise.
	(x86_linux_get_thread_area): Likewise.
	(super_post_startup_inferior): Likewise.
	(x86_linux_child_post_startup_inferior): Likewise.
	(AMD64_LINUX_USER64_CS): Likewise.
	(AMD64_LINUX_X32_DS): Likewise.
	(x86_linux_read_description): Likewise.
	(x86_linux_enable_btrace): Likewise.
	(x86_linux_disable_btrace): Likewise.
	(x86_linux_teardown_btrace): Likewise.
	(x86_linux_read_btrace): Likewise.
	(x86_linux_create_target): Likewise.
	(x86_linux_register_target): Likewise.
Tidy #include lists

This commit tidies up the #include lists in {i386,amd64}-linux-nat.c,
removing headers that are no longer required and reordering some lines
so that both files roughly match.  Additionally, an unused definition
was removed from the middle of the #include list in i386-linux-nat.c.

gdb/
2014-06-27  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c (gdbcore.h): Removed include.
	(regset.h): Likewise.
	(nat/linux-btrace.h): Likewise.
	(btrace.h): Likewise.
	(gdb_assert.h): Likewise.
	(string.h): Likewise.
	(sys/uio.h): Likewise.
	(sys/debugreg.h): Likewise.
	(sys/syscall.h): Likewise.
	(sys/procfs.h): Likewise.
	(sys/user.h): Likewise.
	(asm/ptrace.h): Likewise.
	(i386-nat.h): Likewise.
	* i386-linux-nat.c (i386-nat.h): Likewise.
	(regset.h): Likewise.
	(target.h): Likewise.
	(linux-nat.h): Likewise.
	(nat/linux-btrace.h): Likewise.
	(btrace.h): Likewise.
	(gdb_assert.h): Likewise.
	(string.h): Likewise.
	(sys/uio.h): Likewise.
	(sys/user.h): Likewise.
	(sys/procfs.h): Likewise.
	(sys/reg.h): Likewise.
	(sys/debugreg.h): Likewise.
	(ORIG_EAX): Removed definition.