Compilation warning fixes on 32b platfrom with IAR

Fix compilation warnings with IAR toolchain, on 32 bit platform.
Reported by rahmanih in #683

This is based on work by Ron Eldor in PR #750, some of which was independently
fixed by Azim Khan and already merged in PR #1646.
diff --git a/ChangeLog b/ChangeLog
index ddd5673..0646e6c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -19,6 +19,8 @@
      curves as well as RSA. Fixes #777 found by dbedev.
    * Fix for redefinition of _WIN32_WINNT to avoid overriding a definition
      used by user applications. Found and fixed by Fabio Alessandrelli.
+   * Fix compilation warnings with IAR toolchain, on 32 bit platform.
+     Reported by rahmanih in #683
 
 Changes
    * Changed CMake defaults for IAR to treat all compiler warnings as errors.