I know that you don't care neither for Solaris, nor for SPARC, but maybe you want to apply my diff anyway.
I've got saga-2.0.7 with Unicode enabled.
Loading that sample .grd from https://sourceforge.net/apps/trac/saga-gis/wiki/Climbing%20Mount%20St.%20Helens resulted in crashes due to
- NULL given to wxString::Format("%s")
- const char given to wxString::Format("%s")
at various places.
For details, see attached diff.