ZJIT: Fix binding to `INVALID_SHAPE_ID` under `-std=c99 -pedantic`

```
  /src/jit.c:19:5: error: ISO C restricts enumerator values to range of 'int' (4294967295 is too large) [-Werror,-Wpedantic]
     19 |     RB_INVALID_SHAPE_ID = INVALID_SHAPE_ID,
        |     ^                     ~~~~~~~~~~~~~~~~
```

1 files changed, 5 insertions, 0 deletions

diff --git a/jit.c b/jit.c
index b7cb05d1c3..db3fe097ef 100644
--- a/jit.c
+++ b/jit.c
@@ -22,6 +22,11 @@ enum robject_offsets {
     ROBJECT_OFFSET_AS_ARY = offsetof(struct RObject, as.ary),
 };
 
+// Manually bound in rust since this is out-of-range of `int`,
+// so this can't be in a `enum`, and we avoid `static const`
+// to avoid allocating storage for the constant.
+const shape_id_t rb_invalid_shape_id = INVALID_SHAPE_ID;
+
 unsigned int
 rb_iseq_encoded_size(const rb_iseq_t *iseq)
 {