Index: src/cpu/x86/lapic/Makefile.inc
===================================================================
--- src/cpu/x86/lapic/Makefile.inc	(revision 4995)
+++ src/cpu/x86/lapic/Makefile.inc	(working copy)
@@ -1,4 +1,4 @@
 obj-y += lapic.o
 obj-y += lapic_cpu_init.o
 obj-y += secondary.o
-
+obj-$(CONFIG_UDELAY_LAPIC) += apic_timer.o
Index: src/cpu/x86/tsc/Makefile.inc
===================================================================
--- src/cpu/x86/tsc/Makefile.inc	(revision 4995)
+++ src/cpu/x86/tsc/Makefile.inc	(working copy)
@@ -1,2 +1,2 @@
-obj-y += delay_tsc.o
+obj-$(CONFIG_UDELAY_TSC) += delay_tsc.o