sat-solver: Remove redundant extern "C" definitions.
sat-solver: Remove redundant extern "C" definitions.

These prevents the need to maintain argument changes in them.

opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,ampli/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,linas/link-grammar,ampli/link-grammar,MadBomber/link-grammar,MadBomber/link-grammar,linas/link-grammar,opencog/link-grammar,MadBomber/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,MadBomber/link-grammar,MadBomber/link-grammar,opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,opencog/link-grammar,MadBomber/link-grammar,linas/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,MadBomber/link-grammar,ampli/link-grammar,MadBomber/link-grammar,linas/link-grammar,linas/link-grammar,linas/link-grammar