Allow users to pass a cpuset

If using a new book, MAKEFLAGS is set to -j$(nproc), so that if
we want to easure timings with 4 processors and our computer has
more than that, we need to restrict the number of processors.
Jhalfs allows to do that using th cpuset cgroup controller, so that
it only restrits the make job and not the whole machine. For that
use a small scripts written by Xi Ruoyao that restarts make this
the cpuset set.

LFS/master.sh

@@ -302,6 +302,17 @@ build_Makefile() {           #
     i=`expr $i + 1`
   done
 
+  # If CPUSET is defined and not equal to "all", then we define a first target
+  # that calls a script which re-enters make calling target all
+  if [ -n "$CPUSET" ] && [ "$CPUSET" != all ]; then
+(
+    cat << EOF
+
+all-with-cpuset:
+	@CPUSPEC="\$(CPUSET)" ./run-in-cgroup \$(MAKE) all
+EOF
+) >> $MKFILE
+  fi
   # Drop in the main target 'all:' and the chapter targets with each sub-target
   # as a dependency. Also prevent running targets in parallel.
 (

common/libs/func_wrt_Makefile

@@ -44,6 +44,7 @@ ADD_CUSTOM_TOOLS = $CUSTOM_TOOLS
 ADD_BLFS_TOOLS   = $BLFS_TOOL
 PKGMNGT          = $PKGMNGT
 WRAP_INSTALL     = $WRAP_INSTALL
+CPUSET           = $CPUSET
 
 
 export PATH := \${PATH}:/usr/sbin

jhalfs

@@ -323,7 +323,7 @@ if [[ "$REBUILD_MAKEFILE" = "n" ]] ; then
   true >"$LOGDIR/$LOG"
 
 # Copy common helper files
-  cp "$COMMON_DIR"/{makefile-functions,progress_bar.sh} "$JHALFSDIR/"
+  cp "$COMMON_DIR"/{makefile-functions,progress_bar.sh,run-in-cgroup.sh} "$JHALFSDIR/"
 
 # Copy needed stylesheets
   cp "$COMMON_DIR"/{packages.xsl,chroot.xsl,kernfs.xsl} "$JHALFSDIR/"