Bug#30951: makedate returns different results depending on version of mysql

makedate() will fold years below 100 into the 1970-2069 range. CS removes code
that also wrongly folded years between 100 and 200 into that range, which should
be left unchanged. Backport from 5.1.


mysql-test/r/func_sapdb.result:
  Show that makedate() works correctly for 100 <= year < 200.
mysql-test/t/func_sapdb.test:
  Show that makedate() works correctly for 100 <= year < 200.
sql-common/my_time.c:
  Remove unnecessary date magic. Syncs behaviour with 5.1+
  and manual.

mysql-test/r/func_sapdb.result

@@ -93,6 +93,9 @@ makedate(9999,365)
 select makedate(9999,366);
 makedate(9999,366)
 NULL
+select makedate(100,1);
+makedate(100,1)
+0100-01-01
 select addtime("1997-12-31 23:59:59.999999", "1 1:1:1.000002");
 addtime("1997-12-31 23:59:59.999999", "1 1:1:1.000002")
 1998-01-02 01:01:01.000001

mysql-test/t/func_sapdb.test

@@ -47,6 +47,7 @@ select makedate(1997,1);
 select makedate(1997,0);
 select makedate(9999,365);
 select makedate(9999,366);
+select makedate(100,1);
 
 #Time functions
 

sql-common/my_time.c

@@ -769,11 +769,6 @@ long calc_daynr(uint year,uint month,uint day)
 
   if (year == 0 && month == 0 && day == 0)
     DBUG_RETURN(0);				/* Skip errors */
-  if (year < 200)
-  {
-    if ((year=year+1900) < 1900+YY_PART_YEAR)
-      year+=100;
-  }
   delsum= (long) (365L * year+ 31*(month-1) +day);
   if (month <= 2)
       year--;