diff -Naur a/mozilla/nsprpub/pr/src/io/prprf.c b/mozilla/nsprpub/pr/src/io/prprf.c
--- a/mozilla/nsprpub/pr/src/io/prprf.c	2016-12-15 14:35:07.756707522 -0800
+++ b/mozilla/nsprpub/pr/src/io/prprf.c	2016-12-15 14:35:59.509256020 -0800
@@ -814,7 +814,11 @@
 	    type = TYPE_INT64;
 	    c = *fmt++;
 	} else if (c == 'l') {
+#if PR_BYTES_PER_LONG == 8
+	    type = TYPE_INT64;
+#else
 	    type = TYPE_INT32;
+#endif
 	    c = *fmt++;
 	    if (c == 'l') {
 		type = TYPE_INT64;