upas/common: rename aux to auxx

TBR=rsc
https://codereview.appspot.com/107760043
diff --git a/src/cmd/upas/common/aux.c b/src/cmd/upas/common/auxx.c
similarity index 100%
rename from src/cmd/upas/common/aux.c
rename to src/cmd/upas/common/auxx.c
diff --git a/src/cmd/upas/common/mkfile b/src/cmd/upas/common/mkfile
index 5cd0123..8b70c2b 100644
--- a/src/cmd/upas/common/mkfile
+++ b/src/cmd/upas/common/mkfile
@@ -4,7 +4,7 @@
 
 OFILES=\
 	appendfiletombox.$O\
-	aux.$O\
+	auxx.$O\
 	config.$O\
 	libsys.$O\
 	mail.$O\