diff --git a/ChangeLog b/ChangeLog
index 5d801a35ad..1fe019e93f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Nov 26 06:06:23 2014  Tanaka Akira  <akr@fsij.org>
+
+	* common.mk: encdb.h and transdb.h depends on $(PREP).
+	  So prebuild files for them in tarball are useless.
+
 Wed Nov 26 02:08:44 2014  Tanaka Akira  <akr@fsij.org>
 
 	* tool/make-snapshot: Don't generate enc/trans/newline.c in tarball.
diff --git a/common.mk b/common.mk
index 9d68d0f5a9..88aac1e1de 100644
--- a/common.mk
+++ b/common.mk
@@ -734,8 +734,8 @@ srcs-enc: $(ENC_MK)
 	$(ECHO) making srcs under enc
 	$(Q) $(MAKE) -f $(ENC_MK) RUBY="$(MINIRUBY)" MINIRUBY="$(MINIRUBY)" $(MFLAGS) srcs
 
-all-incs: incs
-incs: $(INSNS) {$(VPATH)}node_name.inc {$(VPATH)}encdb.h {$(VPATH)}transdb.h {$(VPATH)}known_errors.inc \
+all-incs: incs {$(VPATH)}encdb.h {$(VPATH)}transdb.h
+incs: $(INSNS) {$(VPATH)}node_name.inc {$(VPATH)}known_errors.inc \
       $(srcdir)/revision.h $(REVISION_H) enc/unicode/name2ctype.h enc/jis/props.h \
       {$(VPATH)}id.h {$(VPATH)}probes.dmyh