fix(x/tx): fix int64 usage for 32 bit platforms (#15849)

x/tx/CHANGELOG.md

@@ -39,6 +39,9 @@ Ref: https://keepachangelog.com/en/1.0.0/
   * `GetSignersOptions` has been renamed to `signing.Options` and requires `address.Codec`s for account and validator addresses
   * `GetSignersOptions.ProtoFiles` has been renamed to `signing.Options.FileResolver`
 
+### Bug Fixes
+* [#15849](https://github.com/cosmos/cosmos-sdk/pull/15849) Fix int64 usage for 32 bit platforms.
+
 ## v0.5.1
 
 ### Features

x/tx/signing/aminojson/time.go

@@ -46,7 +46,7 @@ func marshalTimestamp(message protoreflect.Message, writer io.Writer) error {
 
 // MaxDurationSeconds the maximum number of seconds (when expressed as nanoseconds) which can fit in an int64.
 // gogoproto encodes google.protobuf.Duration as a time.Duration, which is 64-bit signed integer.
-const MaxDurationSeconds = int64(math.MaxInt64/int(1e9)) - 1
+const MaxDurationSeconds = int64(math.MaxInt64)/1e9 - 1
 
 func marshalDuration(message protoreflect.Message, writer io.Writer) error {
 	fields := message.Descriptor().Fields()