Clean pre-Bash build artifacts before building the Linux kernel

All of these are archived, in a compressed form, in base.tar.bz2.

steps/improve/clean_artifacts.sh

@@ -0,0 +1,13 @@
+# SPDX-FileCopyrightText: 2024 Gábor Stefanik <netrolller.3d@gmail.com>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Delete build artifacts to free up space for Linux kernel build
+
+for pkg in $(ls "${SRCDIR}"); do
+    if [ -d "${SRCDIR}/${pkg}/build" ]; then
+        rm -rf "${SRCDIR}/${pkg}/build"
+    fi
+done
+
+rm -rf "/${ARCH_DIR}/artifact"

steps/manifest

@@ -123,6 +123,7 @@ define: BUILD_LINUX = ( CHROOT == False || BUILD_KERNELS == True )
 build: kexec-linux-1.0.0 ( BUILD_LINUX == True )
 build: kexec-tools-2.0.22 ( BUILD_LINUX == True )
 improve: clean_sources
+improve: clean_artifacts
 build: linux-4.9.10 ( BUILD_LINUX == True )
 jump: break ( INTERNAL_CI == pass1 )
 improve: populate_device_nodes