From 2a42078e9a6ca920a342264b5caf4c8571316cbd Mon Sep 17 00:00:00 2001
From: John Ralls <jralls@ceridwen.us>
Date: Sat, 30 May 2020 15:18:18 -0700
Subject: [PATCH] Prevent libstdc++ copysign declaration error on Win32.

---
 gnucash/gnucash-core-app.hpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gnucash/gnucash-core-app.hpp b/gnucash/gnucash-core-app.hpp
index e7e53553c9..e185758874 100644
--- a/gnucash/gnucash-core-app.hpp
+++ b/gnucash/gnucash-core-app.hpp
@@ -24,6 +24,9 @@
 #ifndef GNUCASH_CORE_APP_HPP
 #define GNUCASH_CORE_APP_HPP
 
+#ifdef __MINGW32__
+#undef _GLIBCXX_USE_C99_MATH_TR1 // Avoid cmath missing function decl.
+#endif
 #include <boost/program_options.hpp>
 #include <string>
 #include <vector>