[master] 34fa018 document #2603

[Nils Goroll]

commit 34fa01836e59369b6884dd122c2e8004f3054546
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Wed Mar 14 10:18:47 2018 +0100

    document #2603

diff --git a/doc/changes.rst b/doc/changes.rst
index e7cab57..30fb551 100644
--- a/doc/changes.rst
+++ b/doc/changes.rst
@@ -129,6 +129,16 @@ VCL and bundled VMODs
   words, all parameters to the shard director ``.backend()`` method
   now need to be named.
 
+* Integers in VCL are now 64 bits wide across all platforms
+  (implemented as ``int64_t`` C type) , but due to implementation
+  specifics of the VCL compiler (VCC), integer literals' precision is
+  limited to that of a VCL real (``double`` C type, roughly 53 bits).
+
+  In effect, larger integers are not represented accurately (they get
+  rounded) and may even have their sign changed or trigger a C
+  compiler warning / error.
+
+
 Logging / statistics
 --------------------