2.5.1 iseq patch to fix ruby for bootsnap

iseq_fix.patch

--- a/compile.c	2018-05-13 19:35:50.000000000 -0700
+++ b/compile.c	2018-05-13 19:34:53.000000000 -0700
@@ -4569,6 +4569,7 @@
     DECL_ANCHOR(else_seq);
     LABEL *then_label, *else_label, *end_label;
     VALUE branches = 0;
+    int ci_size, ci_kw_size;
 
     INIT_ANCHOR(cond_seq);
     INIT_ANCHOR(then_seq);
@@ -4579,8 +4580,20 @@
 
     compile_branch_condition(iseq, cond_seq, node->nd_cond,
 			     then_label, else_label);
+    ci_size = iseq->body->ci_size;
+    ci_kw_size = iseq->body->ci_kw_size;
     CHECK(COMPILE_(then_seq, "then", node_body, popped));
+    if (!then_label->refcnt) {
+      iseq->body->ci_size = ci_size;
+      iseq->body->ci_kw_size = ci_kw_size;
+    }
+    ci_size = iseq->body->ci_size;
+    ci_kw_size = iseq->body->ci_kw_size;
     CHECK(COMPILE_(else_seq, "else", node_else, popped));
+    if (!else_label->refcnt) {
+      iseq->body->ci_size = ci_size;
+      iseq->body->ci_kw_size = ci_kw_size;
+    }
 
     ADD_SEQ(ret, cond_seq);
 
@@ -8513,6 +8526,7 @@
     for (i=0; i<ci_kw_size; i++) {
 	const struct rb_call_info_kw_arg *kw_arg = dump_ci_kw_entries[i].kw_arg;
 	int j;
+	assert(kw_arg != NULL);
 	VALUE *keywords = ALLOCA_N(VALUE, kw_arg->keyword_len);
 	for (j=0; j<kw_arg->keyword_len; j++) {
 	    keywords[j] = (VALUE)ibf_dump_object(dump, kw_arg->keywords[j]); /* kw_arg->keywords[n] is Symbol */
@@ -8622,7 +8636,15 @@
 		rb_raise(rb_eRuntimeError, "path object size mismatch");
 	    }
 	    path = rb_fstring(RARRAY_AREF(pathobj, 0));
-	    realpath = rb_fstring(RARRAY_AREF(pathobj, 1));
+	    realpath = RARRAY_AREF(pathobj, 1);
+	    if (!NIL_P(realpath)) {
+		if (!RB_TYPE_P(realpath, T_STRING)) {
+		    rb_raise(rb_eArgError, "unexpected realpath %"PRIxVALUE
+			     "(%x), path=%+"PRIsVALUE,
+			     realpath, TYPE(realpath), path);
+		}
+		realpath = rb_fstring(realpath);
+	    }
 	}
 	else {
 	    rb_raise(rb_eRuntimeError, "unexpected path object");