Fix "make TAGS" in libdecnumber

[Eli Zaretskii]

"make TAGS" in the GDB source tree fails because libdecnumber doesn't
have a TAGS target.  This patch fixes that:

commit 53bef1c10759f1fd7faf675459871b2f4cc12e53
Author: Eli Zaretskii <eliz@gnu.org>
Date:   Thu Jan 22 21:07:31 2015 +0200

    Another part of fixing "make TAGS".
    
    libdecnumber/
    2015-01-22  Eli Zaretskii  <eliz@gnu.org>
    
    	* Makefile.in (TAGS): New target, to avoid failures in "make TAGS".

diff --git a/libdecnumber/ChangeLog b/libdecnumber/ChangeLog
index 65d20fc..ec6ea1a 100644
--- a/libdecnumber/ChangeLog
+++ b/libdecnumber/ChangeLog
@@ -1,3 +1,7 @@
+2015-01-22  Eli Zaretskii  <eliz@gnu.org>
+
+	* Makefile.in (TAGS): New target, to avoid failures in "make TAGS".
+
 2014-01-23  Marek Polacek  <polacek@redhat.com>
 
 	PR c/59871
diff --git a/libdecnumber/Makefile.in b/libdecnumber/Makefile.in
index b6f3842..8dbada9 100644
--- a/libdecnumber/Makefile.in
+++ b/libdecnumber/Makefile.in
@@ -167,6 +167,8 @@ maintainer-clean: distclean
 	@echo "it deletes files that may require special tools to rebuild."
 	-rm -f $(srcdir)/configure $(srcdir)/aclocal.m4
 
+TAGS:
+
 check:
 installcheck:
 dvi: