diff --git a/src/lib/fmt/SystemError.cxx b/src/lib/fmt/SystemError.cxx
index 01fc20fdb..c3bf104bc 100644
--- a/src/lib/fmt/SystemError.cxx
+++ b/src/lib/fmt/SystemError.cxx
@@ -4,8 +4,6 @@
 #include "SystemError.hxx"
 #include "ToBuffer.hxx"
 
-#include <array>
-
 std::system_error
 VFmtSystemError(std::error_code code,
 		fmt::string_view format_str, fmt::format_args args) noexcept
@@ -16,6 +14,8 @@ VFmtSystemError(std::error_code code,
 
 #ifdef _WIN32
 
+#include <array>
+
 #include <windef.h> // for HWND (needed by winbase.h)
 #include <winbase.h> // for FormatMessageA()