Always link libm for integration tests
It only needs to be added for Linux, but it doesn't hurt anything on macOS.  Work-around for until `-lm` is added by default.
@@ -80,6 +80,7 @@ fn compile(file: &str, name: &str) -> Result<PathBuf, Output> {
// Turn off optimizations as work-around for debug info bug in EIR
.arg("-O0")
.arg("-lc")
+ .arg("-lm")
.arg("--emit=all");
let erlang_path = directory_path.join(file_stem).join(name).join("init.erl");
