From 77a94b6d73f174881bb05a0e7c16b2a25f22c34f Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Thu, 28 May 2020 13:37:20 +0200
Subject: [PATCH] Ccompilation error fixed on gcc-9

---
 src/include/units/bits/external/hacks.h | 6 ++++++
 src/include/units/random.h              | 1 -
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/include/units/bits/external/hacks.h b/src/include/units/bits/external/hacks.h
index e070089c..674ca8d7 100644
--- a/src/include/units/bits/external/hacks.h
+++ b/src/include/units/bits/external/hacks.h
@@ -77,11 +77,17 @@ namespace std {
   using concepts::default_constructible;
   using concepts::derived_from;
   using concepts::equality_comparable_with;
+  // using concepts::floating_point;
+  using concepts::integral;
   using concepts::regular;
   using concepts::same_as;
   using concepts::totally_ordered;
   using concepts::totally_ordered_with;
 
+  // missing in Range-v3
+  template<class T>
+  concept floating_point = std::is_floating_point_v<T>;
+
   template<class F, class... Args>
   concept invocable =
   requires(F&& f, Args&&... args) {
diff --git a/src/include/units/random.h b/src/include/units/random.h
index 6ad373fc..97000502 100644
--- a/src/include/units/random.h
+++ b/src/include/units/random.h
@@ -24,7 +24,6 @@
 
 #include <random>
 #include <functional>
-#include <concepts>
 #include <units/concepts.h>
 
 namespace units {