Compile cbmc with NDEBUG using gcc tool chain on linux.#1477

Merged

tautschnig merged 2 commits intodiffblue:developfrom

andreast271:travis-NDEBUG-build

Nov 30, 2017

Commits on Oct 30, 2017

Create separate clang build with NDEBUG and CPROVER_INVARIANT_DO_NOT_CHECK
andreast271
committed

Commits on Nov 1, 2017

Remove extra build with NDEBUG that compiles but doesn't test.
andreast271
committed