Fix dlmalloc build.

Change-Id: Ied542c40867ab443cdd2076bd2e535b00c4854e4
diff --git a/libc/bionic/dlmalloc.c b/libc/bionic/dlmalloc.c
index fdb1b26..5853e7c 100644
--- a/libc/bionic/dlmalloc.c
+++ b/libc/bionic/dlmalloc.c
@@ -66,13 +66,13 @@
   return 0;
 }
 
-struct mallinfo __mallinfo_arena_info(size_t) {
+struct mallinfo __mallinfo_arena_info(size_t aidx __unused) {
   struct mallinfo mi;
   memset(&mi, 0, sizeof(mi));
   return mi;
 }
 
-struct mallinfo __mallinfo_bin_info(size_t, size_t) {
+struct mallinfo __mallinfo_bin_info(size_t aidx __unused, size_t bidx __unused) {
   struct mallinfo mi;
   memset(&mi, 0, sizeof(mi));
   return mi;