Merging of projects/armv6, part 3

r238211:
Support TARGET_ARCH=armv6 and TARGET_ARCH=armv6eb

This adds a new TARGET_ARCH for building on ARM
processors that support the ARMv6K multiprocessor
extensions.  In particular, these processors have
better support for TLS and mutex operations.

This mostly touches a lot of Makefiles to extend
existing patterns for inferring CPUARCH from ARCH.
It also configures:
 * GCC to default to arm1176jz-s
 * GCC to predefine __FreeBSD_ARCH_armv6__
 * gas to default to ARM_ARCH_V6K
 * uname -p to return 'armv6'
 * make so that MACHINE_ARCH defaults to 'armv6'
It also changes a number of headers to use
the compiler __ARM_ARCH_XXX__ macros to configure
processor-specific support routines.

Submitted by:	Tim Kientzle <kientzle@freebsd.org>

Makefile

@@ -135,7 +135,7 @@ _MAKE=	PATH=${PATH} ${BINMAKE} -f Makefile.inc1 TARGET=${_TARGET} TARGET_ARCH=${
 _TARGET_ARCH=	${TARGET:S/pc98/i386/}
 .elif !defined(TARGET) && defined(TARGET_ARCH) && \
     ${TARGET_ARCH} != ${MACHINE_ARCH}
-_TARGET=		${TARGET_ARCH:C/mips(n32|64)?(el)?/mips/:C/armeb/arm/}
+_TARGET=		${TARGET_ARCH:C/mips(n32|64)?(el)?/mips/:C/arm(v6)?(eb)?/arm/}
 .endif
 # Legacy names, for another transition period mips:mips(n32|64)?eb -> mips:mips\1
 .if defined(TARGET) && defined(TARGET_ARCH) && \
@@ -329,7 +329,7 @@ kernel-toolchains:
 #
 .if make(universe) || make(universe_kernels) || make(tinderbox) || make(targets)
 TARGETS?=amd64 arm i386 ia64 mips pc98 powerpc sparc64
-TARGET_ARCHES_arm?=	arm armeb
+TARGET_ARCHES_arm?=	arm armeb armv6 armv6eb
 TARGET_ARCHES_mips?=	mipsel mips mips64el mips64 mipsn32
 TARGET_ARCHES_powerpc?=	powerpc powerpc64
 TARGET_ARCHES_pc98?=	i386