+# No virtual memory code yet.
+#vm_SRC = vm/filename.c # Some file.
+
+# Filesystem code.
+filesys_SRC = filesys/filesys.c # Filesystem core.
+filesys_SRC += filesys/file.c # Files.
+filesys_SRC += filesys/directory.c # Directories.
+filesys_SRC += filesys/inode.c # File headers.
+filesys_SRC += filesys/fsutil.c # Utilities.
+
+SOURCES = $(foreach dir,$(SUBDIRS),$($(subst /,_,$(dir))_SRC))