MFV r260708
4427 pid provider rejects probes with valid UTF-8 names
This make use of Solaris' u8_validate() which we happen to
use since r185029 for ZFS.
Use of u8_textprep.c required -Wno-cast-qual for powerpc.
Illumos Revision: 1444d846b126463eb1059a572ff114d51f7562e5
Reference:
https://www.illumos.org/issues/4427
Obtained from: Illumos