--- swift/stdlib/public/Platform/glibc.modulemap.gyb.orig	2026-09-13 22:35:30 UTC
+++ swift/stdlib/public/Platform/glibc.modulemap.gyb
@@ -18,7 +18,7 @@
 ///
 /// It's not named just Glibc so that it doesn't conflict in the event of a
 /// future official glibc modulemap.
-module SwiftGlibc [system] {
+module SwiftGlibc [system] [no_undeclared_includes] {
 % if CMAKE_SDK in ["LINUX", "FREEBSD", "OPENBSD"]:
       link "m"
 % end
@@ -42,6 +42,10 @@ module SwiftGlibc [system] {
 % end
 
   header "SwiftGlibc.h"
+
+% if CMAKE_SDK == "FREEBSD":
+  use signal_h
+% end
 
   // <assert.h>'s use of NDEBUG requires textual inclusion. 
   textual header "assert.h"