Switch earmv6{,hf}eb to BE8 in kernel side.

My strategy here is to define _ARM_ARCH_BE8 macro in arm/cdefs.h, if
__ARMEB__ && _ARM_ARCH_6.

Use this macro to determine whether system is compiled for and running on
BE8 mode or not.

Note that, for __ARMEB__, some conditions become compile-time constants
determined by _ARM_ARCH_BE8 macro, e.g., whether BE8 or BE32 are accepted
as a userland binary, or unaligned memory access is possible or not.

If neither COMPAT_NETBSD32 nor MODULAR is defined, there's
no chance for lwp to be running under COMPAT_NETBSD32.

Suggested by mrg.

Test (epp->ep_esch->es_emul != &emul_netbsd) instead of
(epp->ep_esch->es_emul == &emul_netbsd32) to determine whether curlwp is
running on COMPAT_NETBSD32 or not.

The former is possible even if COMPAT_NETBSD32 is not built in the main
kernel. Now, compat_netbsd32 module can work on !COMPAT_NETBSD32 kernel.

Discussed with pgoyette.

XXX
Apply similar fixes, i.e., drop ``#ifdef COMPAT_NETBSD32'' conditional
codes from the rest parts of MD codes for aarch64 and mips64.

ARM spells the System Control Register SCTLR

branches: 1.9.6;
Make sure to clear MDLWP_NOALIGNFLT on !aapcs or !(armv6 && armv7)

branches: 1.8.2;
If we are exec'ing AAPCS and running on armv6+, disable alignment faults
since gcc 4.8 will generate code that uses unaligned accesses.

Read the right register for checking big endianess.

Missing subject.

Support an optional MARCH ELF tag.
Store the MACHINE_ARCH of the executable in mdproc and override sysctl
so that value returned.

Add EF_ARM_BE8
Make sure that running a program, that it right big-endian format for the
processor. (BE8 for armv7, BE32 for all others).

branches: 1.3.2; 1.3.4; 1.3.6; 1.3.8;
Use oabi instead of atpcs32

back out elf note changes and use EF_ARM_ABIVERS to determine EABI usage.

COMPAT_NETBSD32 support for ARM. Which is strange since ARM is already
32-bits. But the newer ARM ABI AAPCS changes the alignment of 64-bit
fields so structures need to copied in and out to deal with the alignment
change. This is a kludge but makes debugging of AAPCS support much easier.

If neither COMPAT_NETBSD32 nor MODULAR is defined, there's
no chance for lwp to be running under COMPAT_NETBSD32.

Suggested by mrg.

Test (epp->ep_esch->es_emul != &emul_netbsd) instead of
(epp->ep_esch->es_emul == &emul_netbsd32) to determine whether curlwp is
running on COMPAT_NETBSD32 or not.

The former is possible even if COMPAT_NETBSD32 is not built in the main
kernel. Now, compat_netbsd32 module can work on !COMPAT_NETBSD32 kernel.

Discussed with pgoyette.

XXX
Apply similar fixes, i.e., drop ``#ifdef COMPAT_NETBSD32'' conditional
codes from the rest parts of MD codes for aarch64 and mips64.

ARM spells the System Control Register SCTLR

branches: 1.9.6;
Make sure to clear MDLWP_NOALIGNFLT on !aapcs or !(armv6 && armv7)

branches: 1.8.2;
If we are exec'ing AAPCS and running on armv6+, disable alignment faults
since gcc 4.8 will generate code that uses unaligned accesses.

Read the right register for checking big endianess.

Missing subject.

Support an optional MARCH ELF tag.
Store the MACHINE_ARCH of the executable in mdproc and override sysctl
so that value returned.

Add EF_ARM_BE8
Make sure that running a program, that it right big-endian format for the
processor. (BE8 for armv7, BE32 for all others).

branches: 1.3.2; 1.3.4; 1.3.6; 1.3.8;
Use oabi instead of atpcs32

back out elf note changes and use EF_ARM_ABIVERS to determine EABI usage.

COMPAT_NETBSD32 support for ARM. Which is strange since ARM is already
32-bits. But the newer ARM ABI AAPCS changes the alignment of 64-bit
fields so structures need to copied in and out to deal with the alignment
change. This is a kludge but makes debugging of AAPCS support much easier.