From c3df3d3b652f8bca0a8738749d3714ee2b74a492 Mon Sep 17 00:00:00 2001
From: Mike <me@michaeljperri.com>
Date: Sun, 22 Aug 2021 15:25:50 -0400
Subject: [PATCH] Fix build with clang & C++17 (bessel functions not defined)

---
 src/sfizz/MathHelpers.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sfizz/MathHelpers.h b/src/sfizz/MathHelpers.h
index 0d2fa1b3..556526da 100644
--- a/src/sfizz/MathHelpers.h
+++ b/src/sfizz/MathHelpers.h
@@ -26,7 +26,7 @@
 #include <simde/x86/sse.h>
 #endif
 
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L && defined(__cpp_lib_math_special_functions)
 static double i0(double x) { return std::cyl_bessel_i(0.0, x); }
 #else
 // external Bessel function from cephes