Restore malloc debug.

Some libc changes were preventing the initialization call from being made.
The basic problem appears to be that libc_init_common.c is only built once,
and it's only built for the non-debug libc.

libc/bionic/libc_init_static.c

@@ -68,6 +68,12 @@ __noreturn void __libc_init(uintptr_t *elfdata,
     /* Initialize the C runtime environment */
     __libc_init_common(elfdata);
 
+#ifdef MALLOC_LEAK_CHECK
+    /* setup malloc leak checker, requires system properties */
+    extern void malloc_debug_init(void);
+    malloc_debug_init();
+#endif
+
     /* Several Linux ABIs don't pass the onexit pointer, and the ones that
      * do never use it.  Therefore, we ignore it.
      */