From 591fd1687d2fceee88bbe1fe49ddacb8d1639a68 Mon Sep 17 00:00:00 2001
From: Tristan Brindle <t.c.brindle@gmail.com>
Date: Thu, 24 Jan 2019 15:06:48 +0000
Subject: [PATCH] Only use libstdc++'s constexpr maths functions with GCC

Clang's __builtin_sqrt() etc aren't constexpr

Fixes #7
---
 raytracer.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/raytracer.hpp b/raytracer.hpp
index 3008e44..93aa5d1 100644
--- a/raytracer.hpp
+++ b/raytracer.hpp
@@ -40,7 +40,7 @@ namespace cmath {
 
 // libstdc++ provides some constexpr math functions as an extension, so
 // use them if we can.
-#ifdef __GLIBCXX__
+#if defined(__GLIBCXX__) && !defined(__clang__)
 #define HAVE_CONSTEXPR_STD_MATH
 #endif