Locking (and therefore SMP) is broken on 64-bit linux

[serguei-patchkovskii]

In src.exec/dpexec/dxThreadMain.h, lock_type is defined as:

typedef volatile int lock_type

Then, throughout the code, it is used as:

DXlock(&lock,...)

where DXlock is defined (in src/exec/libdx/lock.c) as:

int DXlock(lock_type *l, int who) { struct _lock *_lock = *(struct _lock **)l;

So, we in fact cast an integer to a pointer - which does not work on 64-bit Linux, where an integer is still 32-bit.

Ooops.