Restore multicore build support with kernel-bootstrap

This was removed as part of the simplify refactor, severely slowing
down qemu and bare-metal builds. Restoring it brings us back to the
same build times that we saw before the refactor.

rootfs.py

@@ -31,6 +31,7 @@ def create_configuration_file(args):
         config.write(f"CHROOT={args.chroot or args.bwrap}\n")
         config.write(f"UPDATE_CHECKSUMS={args.update_checksums}\n")
         config.write(f"JOBS={args.cores}\n")
+        config.write(f"FINAL_JOBS={args.cores}\n")
         config.write(f"INTERNAL_CI={args.internal_ci or False}\n")
         config.write(f"BARE_METAL={args.bare_metal}\n")
         if (args.bare_metal or args.qemu) and not args.kernel:

steps/improve/update_jobs.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+#
+# SPDX-FileCopyrightText: 2024 Gábor Stefanik <[email protected]>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# Update $JOBS once SMP support is available
+
+cat >> /steps/bootstrap.cfg <<- EOF
+JOBS=${FINAL_JOBS}
+EOF
+
+. /steps/bootstrap.cfg
+. /steps/env

steps/manifest

@@ -118,6 +118,7 @@ improve: clean_sources
 build: linux-4.9.10 ( BUILD_LINUX == True )
 jump: break ( INTERNAL_CI == pass1 )
 jump: linux ( CHROOT == False )
+improve: update_jobs
 improve: finalize_fhs
 build: musl-1.2.4
 build: curl-7.88.1