[Ao7bei3s]

C the core language incl. preprocessor _may_ not allow arbitrary code execution during build.

But in the C ecosystem, there are no build systems with fully declarative configuration. Every project is expected to come with build configuration that is both very ad-hoc / unique to the project, and often includes tens of thousands of lines of unreadable auto-generated boilerplate (e.g. if people commit the later stages of auto-tools, which is common practice) which can run arbitrary code. So in practice C is not better at all.

Also, C still has several ways to do file inclusion from arbitrary paths, as well as ways to cause arbitrary long compile times and object size with tiny source code. Compilation time may be guaranteed to be finite, but it is certainly not bounded.