Upstream fix, see: https://github.com/numpy/numpy/pull/27361

Trac: https://trac.macports.org/ticket/73082

diff --git a/numpy/_core/src/umath/string_fastsearch.h b/numpy/_core/src/umath/string_fastsearch.h
index 61abdcb5ad19..96c1e2d30140 100644
--- numpy/_core/src/umath/string_fastsearch.h.orig
+++ numpy/_core/src/umath/string_fastsearch.h
@@ -9,6 +9,7 @@
 #include <wchar.h>

 #include <type_traits>
+#include <cstddef>

 #include <numpy/npy_common.h>