Fixes for __cxa_finalize

  * Ability to register atexit handler from atexit handler
  * Correct way to handle both forms of atexit handler

Bug: https://code.google.com/p/android/issues/detail?id=66595
Bug: 4998315
Change-Id: I39529afaef97b6e1469c21389d54c0d7d175da28
diff --git a/libc/stdlib/atexit.h b/libc/stdlib/atexit.h
index 4b3e5ab..2e88ad6 100644
--- a/libc/stdlib/atexit.h
+++ b/libc/stdlib/atexit.h
@@ -37,10 +37,7 @@
 	int ind;			/* next index in this table */
 	int max;			/* max entries >= ATEXIT_SIZE */
 	struct atexit_fn {
-		union {
-			void (*std_func)(void);
-			void (*cxa_func)(void *);
-		} fn_ptr;
+		void (*cxa_func)(void *);
 		void *fn_arg;		/* argument for CXA callback */
 		void *fn_dso;		/* shared module handle */
 	} fns[1];			/* the table itself */