[KINETIC][SRU][PATCH] UBUNTU: [Packaging] Support arch-specific compilers in updateconfigs

[Dimitri John Ledkov]

BugLink: https://bugs.launchpad.net/bugs/1993120

For some kernels we had to use different toolchain on per-arch
basis. Introduce support for such scenario in kernelconfig
script. This will allow to set gcc=gcc-11 in
debian.flavour/rules.d/arch.mk. Note this doesn't yet generate correct
build-dependencies.

Signed-off-by: Dimitri John Ledkov <dimitri.ledkov at canonical.com>
---
 debian/scripts/misc/kernelconfig | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/debian/scripts/misc/kernelconfig b/debian/scripts/misc/kernelconfig
index 44c1b79d97..d2f94081c3 100755
--- a/debian/scripts/misc/kernelconfig
+++ b/debian/scripts/misc/kernelconfig
@@ -67,12 +67,15 @@ for arch in $archs; do
 	# Determine cross toolchain to use for Kconfig compiler tests
 	cross_compile="$(dpkg-architecture -qDEB_HOST_GNU_TYPE -a$arch 2>/dev/null)-"
 
+	# Arch-specific compiler, if any
+	archgcc=$(echo -e "show-%:\n\t at echo \$(\$*)\ninclude $DEBIAN/rules.d/$arch.mk" | make -s -f - show-gcc)
+
 	# Environment variables for 'make *config'. We omit CROSS_COMPILE
 	# for i386 since it is no longer supported after 19.04, however
 	# we maintain the configs for hwe.
 	modify_config=true
 	env="ARCH=$kernarch DEB_ARCH=$arch"
-	compiler_path=$(which "${cross_compile}${gcc}" || true)
+	compiler_path=$(which "${cross_compile}${archgcc:-$gcc}" || true)
 	if [ "$compiler_path" != '' ]; then
 		env="$env CROSS_COMPILE=$cross_compile CC=$compiler_path"
 	else
-- 
2.34.1