package/linux-headers: drop 6.8.x option

The 6.8.x series is now EOL upstream, so drop the linux-headers option
and add legacy handling for it.

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

Config.in.legacy

@@ -144,7 +144,14 @@ endif
 
 ###############################################################################
 
-comment "Legacy options removed in 2024.05"
+comment "Legacy options removed in 2024.08"
+
+config BR2_KERNEL_HEADERS_6_8
+	bool "kernel headers version 6.8.x are no longer supported"
+	select BR2_LEGACY
+	help
+	  Version 6.8.x of the Linux kernel headers are no longer
+	  maintained upstream and are now removed.
 
 config BR2_TARGET_AT91BOOTSTRAP
 	bool "at91bootstrap removed"

linux/linux.hash

@@ -1,6 +1,5 @@
 # From https://www.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
 sha256  272800e0d1a7d01a78bce95a3aaf5c80816f50eb15c517d7003e58355760ecc2  linux-6.9.4.tar.xz
-sha256  19b31956d229b5b9ca5671fa1c74320179682a3d8d00fc86794114b21da86039  linux-6.8.12.tar.xz
 sha256  a13ebc20dc2a75722699949af74aa86a4ce5d544d6daaa6a7de4e8c81b40de97  linux-6.6.33.tar.xz
 sha256  df31af2ef5923d61fadd68bfd991f50f2e42a913895eb4b03214ee78f8720bcf  linux-6.1.93.tar.xz
 # From https://www.kernel.org/pub/linux/kernel/v5.x/sha256sums.asc

package/linux-headers/Config.in.host

@@ -48,10 +48,6 @@ config BR2_KERNEL_HEADERS_6_6
 	bool "Linux 6.6.x kernel headers"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_6_6
 
-config BR2_KERNEL_HEADERS_6_8
-	bool "Linux 6.8.x kernel headers"
-	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_6_8
-
 config BR2_KERNEL_HEADERS_6_9
 	bool "Linux 6.9.x kernel headers"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_6_9
@@ -429,7 +425,6 @@ config BR2_DEFAULT_KERNEL_HEADERS
 	default "5.15.160"	if BR2_KERNEL_HEADERS_5_15
 	default "6.1.93"	if BR2_KERNEL_HEADERS_6_1
 	default "6.6.33"	if BR2_KERNEL_HEADERS_6_6
-	default "6.8.12"	if BR2_KERNEL_HEADERS_6_8
 	default "6.9.4"		if BR2_KERNEL_HEADERS_6_9
 	default BR2_DEFAULT_KERNEL_VERSION if BR2_KERNEL_HEADERS_VERSION
 	default "custom"	if BR2_KERNEL_HEADERS_CUSTOM_TARBALL