On Oracle Solaris the following statement is declared in file /usr/include/sys/regset.h:
#define SS 18 /* only stored on a privilege transition */

Because of this template type name SS is substituted by numeric literal, which results in a compilation error:
error: expected nested-name-specifier before numeric constant

Fixed by renaming template type names.

Co-authored-by: Roman Degtyar <Roman.Degtyar@veeam.com>