pushbuild fixes to please gcc and darwin/ppc64

include/my_atomic.h:
  transparent_union doesn't work in g++, doesn't work on darwin/ppc64
storage/maria/ma_blockrec.c:
  compiler warning
storage/maria/ma_loghandler.c:
  compiler warning
storage/maria/ma_page.c:
  compiler warning

include/my_atomic.h

@@ -66,7 +66,16 @@
   v=tmp;
 #endif
 
-#ifdef __GNUC__
+/*
+  transparent_union doesn't work in g++
+  Bug ?
+
+  Darwin's gcc doesn't want to put pointers in a transparent_union
+  when built with -arch ppc64. Complains:
+  warning: 'transparent_union' attribute ignored
+*/
+#if defined(__GNUC__) && !defined(__cplusplus) && \
+      ! (defined(__APPLE__) && defined(_ARCH_PPC64))
 /*
   we want to be able to use my_atomic_xxx functions with
   both signed and unsigned integers. But gcc will issue a warning

storage/maria/ma_blockrec.c

@@ -2033,6 +2033,7 @@ static my_bool write_block_record(MARIA_HA *info,
       break;
     default:                                    /* Wrong data */
       DBUG_ASSERT(0);
+      length=0;
       break;
     }
     if (!tmp_data_used && tmp_data + length > end_of_data)

storage/maria/ma_loghandler.c

@@ -676,7 +676,8 @@ const char *maria_data_root;
     cursor               cursor which will be checked
 */
 
-static void translog_check_cursor(struct st_buffer_cursor *cursor)
+static void translog_check_cursor(struct st_buffer_cursor *cursor
+                                 __attribute__((unused)))
 {
   DBUG_ASSERT(cursor->chaser ||
               ((ulong) (cursor->ptr - cursor->buffer->buffer) ==

storage/maria/ma_page.c

@@ -29,7 +29,7 @@ uchar *_ma_fetch_keypage(register MARIA_HA *info,
                          MARIA_PINNED_PAGE **page_link_res)
 {
   uchar *tmp;
-  uint page_size;
+  uint page_size __attribute__((unused));
   MARIA_PINNED_PAGE page_link;
   MARIA_SHARE *share= info->s;
   uint block_size= share->block_size;
@@ -83,7 +83,8 @@ uchar *_ma_fetch_keypage(register MARIA_HA *info,
 
 /* Write a key-page on disk */
 
-int _ma_write_keypage(register MARIA_HA *info, register MARIA_KEYDEF *keyinfo,
+int _ma_write_keypage(register MARIA_HA *info,
+                      register MARIA_KEYDEF *keyinfo __attribute__((unused)),
 		      my_off_t page, enum pagecache_page_lock lock,
                       int level, uchar *buff)
 {