From b392b8214eeb2bcedb8c49d966b673a4e485dba5 Mon Sep 17 00:00:00 2001
From: Artem Pavlenko <artem@mapnik.org>
Date: Mon, 16 Apr 2018 11:10:54 +0200
Subject: [PATCH] add explicit instantiation declarations to DEFINE_ENUM macro
 to fix -Wundefined-var-template warnings.

---
 include/mapnik/enumeration.hpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/mapnik/enumeration.hpp b/include/mapnik/enumeration.hpp
index 60a64016f..38a1b2065 100644
--- a/include/mapnik/enumeration.hpp
+++ b/include/mapnik/enumeration.hpp
@@ -281,7 +281,10 @@ operator<<(std::ostream & os, const mapnik::enumeration<ENUM, THE_MAX> & e)
     using name = enumeration<e, e ## _MAX>;
 #else
 #define DEFINE_ENUM( name, e)                   \
-    using name = enumeration<e, e ## _MAX>;
+    using name = enumeration<e, e ## _MAX>; \
+    template <> MAPNIK_DECL const char ** name ::our_strings_; \
+    template <> MAPNIK_DECL std::string name ::our_name_; \
+    template <> MAPNIK_DECL bool name ::our_verified_flag_;
 #endif
 
 /** Helper macro. Runs the verify_mapnik_enum() method during static initialization.