sim: add distclean dep for gnulib

Makefile.def

diff --git a/Makefile.def b/Makefile.def
index 8701501..15c068e 100644
--- a/Makefile.def
+++ b/Makefile.def
@@ -612,6 +612,7 @@
 // gdb and gdbserver.
 dependencies = { module=distclean-gnulib; on=distclean-gdb; };
 dependencies = { module=distclean-gnulib; on=distclean-gdbserver; };
+dependencies = { module=distclean-gnulib; on=distclean-sim; };
 
 // Warning, these are not well tested.
 dependencies = { module=all-bison; on=all-intl; };

Makefile.in

diff --git a/Makefile.in b/Makefile.in
index c97130a..efe3565 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -66886,6 +66886,7 @@
 check-stageautofeedback-libctf: maybe-all-stageautofeedback-ld
 distclean-gnulib: maybe-distclean-gdb
 distclean-gnulib: maybe-distclean-gdbserver
+distclean-gnulib: maybe-distclean-sim
 all-bison: maybe-all-build-texinfo
 all-flex: maybe-all-build-bison
 all-flex: maybe-all-m4