diff --git a/internal/sysutil/sysutil.go b/internal/sysutil/sysutil.go
index <HASH>..<HASH> 100644
--- a/internal/sysutil/sysutil.go
+++ b/internal/sysutil/sysutil.go
@@ -9,5 +9,5 @@ import "golang.org/x/sys/unix"
 func RlimitStack() (cur uint64, err error) {
 	var r unix.Rlimit
 	err = unix.Getrlimit(unix.RLIMIT_STACK, &r)
-	return r.Cur, err
+	return uint64(r.Cur), err // Type conversion because Cur is one of uint64, int64 depending on unix flavor.
 }
internal/sysutil: Fix build error on FreeBSD due to Rlimit.Cur type mismatch. (#<I>)

Document why type conversion is necessary. Otherwise, it's not clear

that it's neccessary, and we we wouldn't be able to catch breakage if

it were removed.