PR threads/13448
* dwarf2read.c (decode_locdesc): Handle DW_OP_const8u.
For DW_OP_GNU_push_tls_address increment the value, new comment for it.
gdb/testsuite/
PR threads/13448
* gdb.dwarf2/dw2-var-zero-addr.S: New file.
* gdb.dwarf2/dw2-var-zero-addr.exp: New file.
* gdb.threads/tls-var-main.c: New file.
* gdb.threads/tls-var.c: New file.
* gdb.threads/tls-var.exp: New file.