* alloc.c: Remove one incorrect comment and fix another.

src/ChangeLog

@@ -8,6 +8,7 @@
 	GC_MALLOC_CHECK) && GC_MALLOC_CHECK), to match when it's used.
 	(NEED_MEM_INSERT): New macro.
 	(mem_insert, mem_insert_fixup) [!NEED_MEM_INSERT]: Remove; unused.
+	Remove one incorrect comment and fix another.
 
 	Fix minor ralloc.c problems found by static checking.
 	See http://lists.gnu.org/archive/html/emacs-devel/2011-12/msg00720.html

src/alloc.c

@@ -948,9 +948,6 @@ lisp_free (POINTER_TYPE *block)
 /* The entry point is lisp_align_malloc which returns blocks of at most
    BLOCK_BYTES and guarantees they are aligned on a BLOCK_ALIGN boundary.  */
 
-/* Use posix_memalloc if the system has it and we're using the system's
-   malloc (because our gmalloc.c routines don't have posix_memalign although
-   its memalloc could be used).  */
 #if defined (HAVE_POSIX_MEMALIGN) && defined (SYSTEM_MALLOC)
 #define USE_POSIX_MEMALIGN 1
 #endif
@@ -1007,7 +1004,7 @@ struct ablocks
   struct ablock blocks[ABLOCKS_SIZE];
 };
 
-/* Size of the block requested from malloc or memalign.  */
+/* Size of the block requested from malloc or posix_memalign.  */
 #define ABLOCKS_BYTES (sizeof (struct ablocks) - BLOCK_PADDING)
 
 #define ABLOCK_ABASE(block) \