diff -up thunderbird-115.0.1/comm/third_party/rnp/src/libsexp/include/sexp/sexp-error.h.build-rnp thunderbird-115.0.1/comm/third_party/rnp/src/libsexp/include/sexp/sexp-error.h
--- thunderbird-115.0.1/comm/third_party/rnp/src/libsexp/include/sexp/sexp-error.h.build-rnp	2023-07-24 11:38:24.732782411 +0200
+++ thunderbird-115.0.1/comm/third_party/rnp/src/libsexp/include/sexp/sexp-error.h	2023-07-24 11:38:46.824773498 +0200
@@ -32,6 +32,7 @@
 #include <exception>
 #include <iostream>
 #include <string>
+#include <cstdint>
 
 namespace sexp {