write frm pieces contiguously, don't align them on a 4K boundary

(in partition_archive.test frm size goes down 16 times :)

mysql-test/suite/archive/archive.result

@@ -12701,12 +12701,12 @@ CREATE TABLE t1(a INT, b BLOB) ENGINE=archive;
 SELECT DATA_LENGTH, AVG_ROW_LENGTH FROM
 INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test';
 DATA_LENGTH	AVG_ROW_LENGTH
-8608	15
+535	15
 INSERT INTO t1 VALUES(1, 'sampleblob1'),(2, 'sampleblob2');
 SELECT DATA_LENGTH, AVG_ROW_LENGTH FROM
 INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test';
 DATA_LENGTH	AVG_ROW_LENGTH
-8642	4321
+569	284
 DROP TABLE t1;
 SET @save_join_buffer_size= @@join_buffer_size;
 SET @@join_buffer_size= 8192;

mysql-test/suite/archive/partition_archive.result

@@ -15,10 +15,10 @@ ENGINE = ARCHIVE;
 INSERT INTO t1 VALUES(CURRENT_DATE);
 SELECT DATA_LENGTH, INDEX_LENGTH FROM information_schema.TABLES WHERE TABLE_SCHEMA='test' AND TABLE_NAME='t1';
 DATA_LENGTH	INDEX_LENGTH
-8604	0
+520	0
 SELECT DATA_LENGTH, INDEX_LENGTH FROM information_schema.TABLES WHERE TABLE_SCHEMA='test' AND TABLE_NAME='t1';
 DATA_LENGTH	INDEX_LENGTH
-8604	0
+520	0
 DROP TABLE t1;
 drop database if exists db99;
 drop table if exists t1;

sql/table.cc

@@ -2926,7 +2926,6 @@ void append_unescaped(String *res, const char *pos, uint length)
 void prepare_frm_header(THD *thd, uint reclength, uchar *fileinfo,
                         HA_CREATE_INFO *create_info, uint keys, KEY *key_info)
 {
-  ulong length;
   ulong key_comment_total_bytes= 0;
   uint i;
   DBUG_ENTER("prepare_frm_header");
@@ -2947,7 +2946,6 @@ void prepare_frm_header(THD *thd, uint reclength, uchar *fileinfo,
   fileinfo[3]= (uchar) ha_legacy_type(
         ha_checktype(thd,ha_legacy_type(create_info->db_type),0,0));
   int2store(fileinfo+4,3);
-  int2store(fileinfo+6,IO_SIZE);		/* Next block starts here */
   /*
     Keep in sync with pack_keys() in unireg.cc
     For each key:
@@ -2971,10 +2969,7 @@ void prepare_frm_header(THD *thd, uint reclength, uchar *fileinfo,
   key_length= keys * (8 + MAX_REF_PARTS * 9 + NAME_LEN + 1) + 16
               + key_comment_total_bytes;
 
-  length= next_io_size((ulong) (IO_SIZE+key_length+reclength+
-                                create_info->extra_size));
   int2store(fileinfo+8,1);
-  int4store(fileinfo+10,length);
   tmp_key_length= (key_length < 0xffff) ? key_length : 0xffff;
   int2store(fileinfo+14,tmp_key_length);
   int2store(fileinfo+16,reclength);

sql/unireg.cc

@@ -206,24 +206,18 @@ bool mysql_create_frm(THD *thd, const char *file_name,
   prepare_frm_header(thd, reclength, fileinfo, create_info, keys, key_info);
 
   key_buff_length= uint4korr(fileinfo+47);
-  filepos= uint4korr(fileinfo+10);
 
-  {
-    size_t len1, len2, len3;
-    len1= FRM_HEADER_SIZE; // fileinfo
-    len1+= 7; // "form entry"
-
-    len2= uint2korr(fileinfo+6); // 4096
-    len2+= key_buff_length;
-    len2+= reclength;
-    len2+= create_info->extra_size;
+  frm_length= FRM_HEADER_SIZE; // fileinfo;
+  frm_length+= 7; // "form entry"
 
-    len3= filepos;
-    len3+= FRM_FORMINFO_SIZE; //forminfo
-    len3+= packed_fields_length(create_fields);
+  int2store(fileinfo+6, frm_length);
+  frm_length+= key_buff_length;
+  frm_length+= reclength; // row with default values
+  frm_length+= create_info->extra_size;
 
-    frm_length= len3;
-  }
+  filepos= frm_length;
+  frm_length+= FRM_FORMINFO_SIZE; // forminfo
+  frm_length+= packed_fields_length(create_fields);
   
   frm_ptr= (uchar*) my_malloc(frm_length, MYF(MY_ZEROFILL | MY_THREAD_SPECIFIC));
   if (!frm_ptr)