math/cvc4: Update 1.5 -> 1.6

Port changes:

• Add dependency on cryptominisat, and the corresponding port option
• Add USES=autoreconf, the suplied configure fails, see https://github.com/CVC4/CVC4/issues/2192
• Now build depends on python
• Force clang-60 to prevent build failures on 10

PR: 229780
Submitted by: Greg V <greg@unrelenting.technology>