package/gcc: restrict gcc 8.x to PowerPC SPE

gcc 11.1 is around, gcc 10.2 is the default version, so drop
8.4 in order to reduce the gcc choice.

For PowerPC SPE, introduce BR2_GCC_VERSION_POWERPC_SPE
to avoid removing defconfigs arcturus_ucp1020_defconfig,
freescale_p1025twr_defconfig and qemu_ppc_mpc8544ds_defconfig
that are still used by some users [1].
BR2_GCC_VERSION_POWERPC_SPE use the same gcc version (8.4), no
change expected.

[1] 96e80ad214ced86c802d561946fa7da88c1595eb

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Oleksandr Zhadan <oleks@arcturusnetworks.com>
Cc: Michael Durrant <mdurrant@ArcturusNetworks.com>
Cc: Matthew Weber <matthew.weber@collins.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

Config.in.legacy

@@ -161,6 +161,15 @@ config BR2_PACKAGE_PHP_EXT_XMLRPC
 	  The XMLRPC php extension was removed.
 	  See: https://wiki.php.net/rfc/unbundle_xmlprc
 
+comment "Legacy options removed in 2021.08"
+
+config BR2_GCC_VERSION_8_X
+	bool "gcc 8.x support removed"
+	select BR2_LEGACY
+	help
+	  Support for gcc version 8.x has been removed. The current
+	  default version (10.x or later) has been selected instead.
+
 comment "Legacy options removed in 2021.05"
 
 config BR2_PACKAGE_UDISKS_LVM2

package/gcc/Config.in.host

@@ -4,6 +4,7 @@ choice
 	prompt "GCC compiler Version"
 	default BR2_GCC_VERSION_ARC if BR2_arc
 	default BR2_GCC_VERSION_CSKY if BR2_csky
+	default BR2_GCC_VERSION_POWERPC_SPE if BR2_powerpc_SPE
 	default BR2_GCC_VERSION_10_X
 	help
 	  Select the version of gcc you wish to use.
@@ -20,11 +21,11 @@ config BR2_GCC_VERSION_CSKY
 	depends on BR2_csky
 	select BR2_TOOLCHAIN_GCC_AT_LEAST_6
 
-config BR2_GCC_VERSION_8_X
-	bool "gcc 8.x"
-	depends on !BR2_ARCH_NEEDS_GCC_AT_LEAST_9
-	# Broken or unsupported architectures
-	depends on !BR2_or1k
+config BR2_GCC_VERSION_POWERPC_SPE
+	bool "gcc powerpc spe"
+	# powerpc spe support has been deprecated since gcc 8.x.
+	# https://gcc.gnu.org/ml/gcc/2018-04/msg00102.html
+	depends on BR2_powerpc_SPE
 	select BR2_TOOLCHAIN_GCC_AT_LEAST_8
 
 config BR2_GCC_VERSION_9_X
@@ -88,7 +89,7 @@ config BR2_GCC_SUPPORTS_DLANG
 
 config BR2_GCC_VERSION
 	string
-	default "8.4.0"     if BR2_GCC_VERSION_8_X
+	default "8.4.0"     if BR2_GCC_VERSION_POWERPC_SPE
 	default "9.4.0"     if BR2_GCC_VERSION_9_X
 	default "10.3.0"    if BR2_GCC_VERSION_10_X
 	default "11.1.0"    if BR2_GCC_VERSION_11_X