Fix for Bug#50221 Server refuses to start from non-default installdir on Solaris 32-bit

When starting mysqld it did not recognize most of the options given on
the command line when it was compiled for 32-bit Solaris using Sun
Studio compiler. The cause for this was that most of the entries in
the my_long_options array contained "garbage" data. The garbage data
was caused by a compiler bug. When initilizing the def_value member
for the "default-storage-engine" entry it was initialized like this:

  (longlong)"MyISAM"

i.e. casting a 32 bit pointer to a 64 bit integer value. Due to the
compiler bug only 4 bytes was allocated (instead of 8 bytes). This
caused everything following this entry to be stored at a location that
was 4 byte wrong.

The fix/work-around for this problem is initialize the def_value
for default-storage-engine in my_long_options to 0 and instead
initialize the default_storage_engine variable to "MyISAM" in
init_common_variables().

sql/mysqld.cc:
  Due to a bug in Sun Studio compiler when generating 32 bit code the 
  initialization of the def_value member of the default-storage-engine entry 
  in my_long_options only got 4 bytes allocated instead of 8 bytes. 
  The compiler bug was triggered by casting a 32 bit pointer to a 64 bit 
  integer value in the initialization code for my_long_options. To avoid 
  triggering the compiler bug the intialization of the def_value in
  my_long_options is set to 0 and instead the default_storage_engine
  is initialized to "MyISAM" in init_common_variables().

sql/mysqld.cc

@@ -3336,6 +3336,16 @@ static int init_common_variables()
   strmake(pidfile_name, default_logfile_name, sizeof(pidfile_name)-5);
   strmov(fn_ext(pidfile_name),".pid");		// Add proper extension
 
+  /*
+    The default-storage-engine entry in my_long_options should have a
+    non-null default value. It was earlier intialized as
+    (longlong)"MyISAM" in my_long_options but this triggered a
+    compiler error in the Sun Studio 12 compiler. As a work-around we
+    set the def_value member to 0 in my_long_options and initialize it
+    to the correct value here.
+  */
+  default_storage_engine="MyISAM";
+
   /*
     Add server status variables to the dynamic list of
     status variables that is shown by SHOW STATUS.
@@ -5953,9 +5963,12 @@ struct my_option my_long_options[]=
   {"default-collation", 0, "Set the default collation (deprecated option, use --collation-server instead).",
    (uchar**) &default_collation_name, (uchar**) &default_collation_name,
    0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0 },
+  /* default-storage-engine should have "MyISAM" as def_value. Instead
+     of initializing it here it is done in init_common_variables() due
+     to a compiler bug in Sun Studio compiler. */
   {"default-storage-engine", 0, "The default storage engine for new tables",
    (uchar**) &default_storage_engine, 0, 0, GET_STR, REQUIRED_ARG,
-   (longlong)"MyISAM", 0, 0, 0, 0, 0 },
+   0, 0, 0, 0, 0, 0 },
   {"default-time-zone", 0, "Set the default time zone.",
    (uchar**) &default_tz_name, (uchar**) &default_tz_name,
    0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0 },