Some variables weren't cleared properly so consequitive embedded server start/stop failed.
Cleanups added. Also mysql_client_test.c extended to test that (taken from Mattias Johnson's patch)
includes:
* remove some remnants of "Bug#14521864: MYSQL 5.1 TO 5.5 BUGS PARTITIONING"
* introduce LOCK_share, now LOCK_ha_data is strictly for engines
* rea_create_table() always creates .par file (even in "frm-only" mode)
* fix a 5.6 bug, temp file leak on dummy ALTER TABLE
Non-blocking client currently can be build on Windows, GCC on i386 and x64, or any OS wth ucontext.h header. Prior to this patch, build failed if neither of these conditions is true.
Fix to avoid compiler errors in these case - non-blocking API would not be useful on , but otherwise everything will work as before.