From 3c6cf877187e8d536c0f990478f4c6544acc61d6 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Sun, 11 Nov 2018 17:12:56 +0000
Subject: [PATCH] Disable external template instances on cygwin - they lead to
 duplicate symbols for some reason. See
 https://github.com/boostorg/regex/issues/64.

---
 include/boost/regex/config.hpp | 4 ++++
 test/Jamfile.v2                | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/boost/regex/config.hpp b/include/boost/regex/config.hpp
index de817dbf..f01321c8 100644
--- a/include/boost/regex/config.hpp
+++ b/include/boost/regex/config.hpp
@@ -120,6 +120,10 @@
 #ifdef __clang__
 #  define BOOST_REGEX_NO_EXTERNAL_TEMPLATES
 #endif
+#ifdef __CYGWIN__
+/* We get multiply defined symbols without this: */
+#  define BOOST_REGEX_NO_EXTERNAL_TEMPLATES
+#endif
 
 /*
  * If there isn't good enough wide character support then there will
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 17f6b842..49ed730b 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -19,7 +19,7 @@ project
       <define>U_USING_ICU_NAMESPACE=0
       #<toolset>gcc-mw:<link>static
       #<toolset>gcc-mingw:<link>static
-      <toolset>gcc-cygwin:<link>static
+      #<toolset>gcc-cygwin:<link>static
       <toolset>sun:<link>static
     ;