gcc/ck_pr: Try to make sure the compiler isn't unhappy about constness.

include/gcc/ck_pr.h

@@ -61,7 +61,7 @@ ck_pr_barrier(void)
 	{							\
 		T r;						\
 		ck_pr_barrier();				\
-		r = CK_PR_ACCESS(*(T *)target);			\
+		r = CK_PR_ACCESS(*(const T *)target);		\
 		ck_pr_barrier();				\
 		return (r);					\
 	}							\
@@ -80,7 +80,7 @@ ck_pr_md_load_ptr(const void *target)
 	void *r;
 
 	ck_pr_barrier();
-	r = CK_PR_ACCESS(*(void **)target);
+	r = CK_CC_DECONST_PTR(CK_PR_ACCESS(target));
 	ck_pr_barrier();
 
 	return r;
@@ -91,7 +91,7 @@ ck_pr_md_store_ptr(void *target, const void *v)
 {
 
 	ck_pr_barrier();
-	CK_PR_ACCESS(*(void **)target) = (void *)v;
+	CK_PR_ACCESS(target) = CK_CC_DECONST_PTR(v);
 	ck_pr_barrier();
 	return;
 }