kbuild: collect minimum tool versions into scripts/min-tool-version.sh

The kernel build uses various tools, many of which are provided by the
same software suite, for example, LLVM and Binutils.

When you raise the minimum version of Clang/LLVM, you need to update
clang_min_version in scripts/cc-version.sh and also lld_min_version in
scripts/ld-version.sh.

Kbuild can handle CC=clang and LD=ld.lld independently, but it does not
make much sense to maintain their versions separately.

Let's create a central place of minimum tool versions so you do not need
to touch multiple files. scripts/min-tool-version.sh prints the minimum
version of the given tool.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh
index 3f2ee88..f1952c5 100755
--- a/scripts/cc-version.sh
+++ b/scripts/cc-version.sh
@@ -6,18 +6,6 @@
 
 set -e
 
-# When you raise the minimum compiler version, please update
-# Documentation/process/changes.rst as well.
-gcc_min_version=4.9.0
-clang_min_version=10.0.1
-icc_min_version=16.0.3 # temporary
-
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
-# https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
-if [ "$SRCARCH" = arm64 ]; then
-	gcc_min_version=5.1.0
-fi
-
 # Print the compiler name and some version components.
 get_compiler_info()
 {
@@ -48,18 +36,20 @@
 
 name=$1
 
+min_tool_version=$(dirname $0)/min-tool-version.sh
+
 case "$name" in
 GCC)
 	version=$2.$3.$4
-	min_version=$gcc_min_version
+	min_version=$($min_tool_version gcc)
 	;;
 Clang)
 	version=$2.$3.$4
-	min_version=$clang_min_version
+	min_version=$($min_tool_version llvm)
 	;;
 ICC)
 	version=$(($2 / 100)).$(($2 % 100)).$3
-	min_version=$icc_min_version
+	min_version=$($min_tool_version icc)
 	;;
 *)
 	echo "$orig_args: unknown compiler" >&2