Implemented a new "bt -A" option for the S390X architecture, which
adds support for displaying the new s390x vector registers.  For
ELF dumps, the registers are taken from the VX ELF notes; for s390
dumps. the registers are taken from memory.  The option produces the
same output as the -a option, but also displays the vector registers
for all active tasks.
(holzheu@linux.vnet.ibm.com)