make JS trunc polyfill opt-in, closes #16144 (#19183)

1 files changed, 7 insertions, 1 deletions

diff --git a/changelog.md b/changelog.md
index b645bc5c7..f7f92ad3c 100644
--- a/changelog.md
+++ b/changelog.md
@@ -3,7 +3,13 @@
 
 ## Changes affecting backward compatibility
 
-
+- The `Math.trunc` polyfill for targeting Internet Explorer was
+  previously emitted for every JavaScript output file except if
+  the symbol `nodejs` was defined via `-d:nodejs`. Now, it is only
+  emitted if the symbol `nimJsMathTruncPolyfill` is defined. If you are
+  targeting Internet Explorer, you may choose to enable this option
+  or define your own `Math.trunc` polyfill using the [`emit` pragma](https://nim-lang.org/docs/manual.html#implementation-specific-pragmas-emit-pragma). Nim uses
+  `Math.trunc` for the division and modulo operators for integers.
 
 ## Standard library additions and changes