mcexec: --disable-sched-yield: avoid kernel/user switch

configure

@@ -634,6 +634,7 @@ KERNDIR
 KMODDIR
 ETCDIR
 SBINDIR
+LIBDIR
 BINDIR
 TARGET
 UNAME_R
@@ -4039,6 +4040,9 @@ case $WITH_TARGET in
 	if test "X$BINDIR" = X; then
 		BINDIR="$prefix/bin"
 	fi
+	if test "X$LIBDIR" = X; then
+		LIBDIR="$prefix/lib"
+	fi
 	if test "X$SBINDIR" = X; then
 		SBINDIR="$prefix/sbin"
 	fi
@@ -4506,6 +4510,15 @@ else
 $as_echo "$as_me: mcoverlayfs is disabled" >&6;}
 fi
 
+if test "x$LIBDIR" != "x" ; then
+
+cat >>confdefs.h <<_ACEOF
+#define MCKERNEL_LIBDIR "$LIBDIR"
+_ACEOF
+
+fi
+
+