This is a fix specific for HPUX,
for which the compiler does not resolve properly dependencies
involving unused inline functions.
(See existing comments in mysql_thread.h)
In include/mysql/psi/mysql_thread.h,
the instrumentation helpers for mysql_prlock_*
uses the pr lock apis.
These apis are implemented in mysys/thr_rwlock.c,
which is not linked to client code.
As a result, the code does not link in libmysql_r, on HPUX.
The fix is to cut dependencies explicitely,
by introducing -DDISABLE_MYSQL_RWLOCK_H,
when building client code.
Before this fix, the performance schema instrumentation
in mdl.h / mdl.cc was incomplete, causing:
- build warnings,
- no data collection for the performance schema
This fix:
- added instrumentation helpers for the new preferred
reader read write lock, mysql_prlock_*
- implemented completely the performance schema
instrumentation of mdl.h / mdl.cc
