From def687462c32ec40757e49eb6069f109d50236d6 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Mon, 14 Nov 2016 20:14:52 -0800
Subject: [PATCH] Fix signbit detection (#423)

---
 fmt/format.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fmt/format.h b/fmt/format.h
index 9f0995ab..1ed934c1 100644
--- a/fmt/format.h
+++ b/fmt/format.h
@@ -397,8 +397,10 @@ class numeric_limits<fmt::internal::DummyInt> :
   // Portable version of signbit.
   static bool isnegative(double x) {
     using namespace fmt::internal;
-    if (const_check(sizeof(signbit(x)) == sizeof(int)))
+    if (const_check(sizeof(signbit(x)) == sizeof(bool) ||
+                    sizeof(signbit(x)) == sizeof(int))) {
       return signbit(x) != 0;
+    }
     if (x < 0) return true;
     if (!isnotanumber(x)) return false;
     int dec = 0, sign = 0;