Fix comparison warning on 32-bit systems
diff --git a/core/Lucy/Store/InStream.c b/core/Lucy/Store/InStream.c
index f35ace9..273a79e 100644
--- a/core/Lucy/Store/InStream.c
+++ b/core/Lucy/Store/InStream.c
@@ -344,9 +344,11 @@
 
 void
 InStream_Read_Bytes_IMP(InStream *self, char* buf, size_t len) {
+#if SIZE_MAX > INT64_MAX
     if (len >= INT64_MAX) {
         THROW(ERR, "Can't read %u64 bytes", (uint64_t)len);
     }
+#endif
     SI_read_bytes(self, buf, (int64_t)len);
 }