diff --git a/gdb/Makefile.dist b/gdb/Makefile.dist
index f7770186260..0e4a788106b 100755
--- a/gdb/Makefile.dist
+++ b/gdb/Makefile.dist
@@ -362,6 +362,8 @@ config.status:
 
 # These are not generated by "make depend" because they only are there
 # for some machines.
+# But these rules don't do what we want; we want to hack the foo.o: tm.h
+# dependency to do the right thing.
 tm-isi.h tm-sun3.h tm-news.h tm-hp300bsd.h tm-altos.h : tm-68k.h
 tm-hp300hpux.h tm-sun2.h tm-3b1.h : tm-68k.h
 xm-news1000.h : xm-news.h
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index f7770186260..0e4a788106b 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -362,6 +362,8 @@ config.status:
 
 # These are not generated by "make depend" because they only are there
 # for some machines.
+# But these rules don't do what we want; we want to hack the foo.o: tm.h
+# dependency to do the right thing.
 tm-isi.h tm-sun3.h tm-news.h tm-hp300bsd.h tm-altos.h : tm-68k.h
 tm-hp300hpux.h tm-sun2.h tm-3b1.h : tm-68k.h
 xm-news1000.h : xm-news.h