diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_NEON.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_NEON.h
new file mode 100644
index 0000000..0a1f695
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_NEON.h
@@ -0,0 +1,12 @@
+// HAVE_NEON
+
+#undef HAVE_NEON
+
+/* GCC, Clang: -mfpu={neon,neon-vfpv3,neon-vfpv4,neon-fp16,..}
+ *
+ * MSVC: Always enabled (and presumably defines at least one of
+ *       __ARM_NEON[__]).
+ */
+#if defined(__ARM_NEON) || defined(__ARM_NEON__)
+#  define HAVE_NEON 1
+#endif