armv6: Remove support for building armv6

With it planned that armv7 will be the only 32-bit kernel when 15.0 is
released remove support for armv6.

Remove the top level build infrastructure. It was already removed from
universe, this just stops it from being built directly.

Reviewed by:	mmel, emaste
Sponsored by:	Arm Ltd
Differential Revision:	https://reviews.freebsd.org/D45634

Makefile

@@ -521,9 +521,6 @@ worlds: .PHONY
 # Don't build rarely used, semi-supported architectures unless requested.
 #
 .if defined(EXTRA_TARGETS)
-# armv6's importance has waned enough to make building it the exception rather
-# than the rule.
-EXTRA_ARCHES_arm=	armv6
 # powerpcspe excluded from main list until clang fixed
 EXTRA_ARCHES_powerpc=	powerpcspe
 .endif
@@ -535,8 +532,7 @@ TARGET_ARCHES_${target}= ${MACHINE_ARCH_LIST_${target}}
 
 .if defined(USE_GCC_TOOLCHAINS)
 TOOLCHAINS_amd64=	amd64-gcc12
-TOOLCHAINS_arm=		armv6-gcc12 armv7-gcc12
-TOOLCHAIN_armv7=	armv7-gcc12
+TOOLCHAINS_arm=		armv7-gcc12
 TOOLCHAINS_arm64=	aarch64-gcc12
 TOOLCHAINS_i386=	i386-gcc12
 TOOLCHAINS_powerpc=	powerpc-gcc12 powerpc64-gcc12

Makefile.inc1

@@ -146,7 +146,6 @@ TARGET_TRIPLE_ABI?=	unknown
 TARGET_TRIPLE?=	${TARGET_ARCH:S/amd64/x86_64/}-${TARGET_TRIPLE_ABI}-freebsd${OS_REVISION}
 KNOWN_ARCHES?=	aarch64/arm64 \
 		amd64 \
-		armv6/arm \
 		armv7/arm \
 		i386 \
 		powerpc \

UPDATING

@@ -27,6 +27,9 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 15.x IS SLOW:
 	world, or to merely disable the most expensive debugging functionality
 	at runtime, run "ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20240712:
+	Support for armv6 has been disconnected and is being removed.
+
 20240617:
 	ifconfig now treats IPv4 addresses without a width or mask as an error.
 	Specify the desired mask or width along with the IP address on the

sys/sys/param.h

@@ -73,7 +73,7 @@
  * cannot include sys/param.h and should only be updated here.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1500019
+#define __FreeBSD_version 1500020
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,