Update MathSAT5 to newly released version 5.6.16

[baierd]

MathSAT5 released version 5.6.16 and we should check it out.

Changelog for version 5.6.16 (Mar 27, 2026):

• Fixed bugs in model generation in the NA solver.
• Fixed bugs in incremental usage with theory combination.
• The Windows version is now built with the MSVC compiler again.

[kfriedberger]

I requested an ARM64 version from Alberto. It is currently missing for v5.6.16. ❌

UPDATE: Alberto reported back: ARM64 is published. ✔️

UPDATE: Library lib/libmathsat.a is missing in the archive. Request sent. ❌

[baierd]

Thank you very much!

I ran it in CPAchecker using all unreach-call tasks of SV-COMP26 (ReachSafety, SoftwareSystems, and Concurrency categories) using the svcomp config against the MathSAT5 version from our 6.0.0 release and it performs slightly better:
mathsat6.0.0.and.6+.comparison.results.2026-04-10_18-43-13.table.html