ClangIR Frontend
Adding ClangIR preprocessing as an integral part of Theta.
Even more importantly, it solves the referencing non-variable stuff.
Modified subprojects (since v7.3.0):
common/core
frontends/c-frontend
solver/solver-smtlib
xcfa/xcfa
xcfa/xcfa-cli
xcfa/xcfa2chc
xsts/xsts-analysis