diff --git a/Makefile.build b/Makefile.build
index e6010c1faa52d376ce3a2c8856c775272b78cf55..cb51428b42b00d988c9a9940537ef8e2fe8b0c7c 100644
--- a/Makefile.build
+++ b/Makefile.build
@@ -62,10 +62,9 @@ userprog_SRC += userprog/exception.c	# User exception handler.
 userprog_SRC += userprog/syscall.c	# System call handler.
 userprog_SRC += userprog/gdt.c		# GDT initialization.
 userprog_SRC += userprog/tss.c		# TSS management.
-userprog_SRC += userprog/syscall_exec.c
+userprog_SRC += userprog/syscall_exit.c
 userprog_SRC += userprog/syscall_open.c
 userprog_SRC += userprog/syscall_halt.c
-userprog_SRC += userprog/syscall_wait.c
 userprog_SRC += userprog/syscall_create.c
 userprog_SRC += userprog/syscall_write.c