Fix duplicate definitions on Mac

1 files changed, 6 insertions, 8 deletions

diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index b6aaed138..2429ddad2 100755
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -189,19 +189,17 @@ template<> struct make_unsigned<signed int>       { typedef unsigned int type; }
 template<> struct make_unsigned<unsigned int>     { typedef unsigned int type; };
 template<> struct make_unsigned<signed long>      { typedef unsigned long type; };
 template<> struct make_unsigned<unsigned long>    { typedef unsigned long type; };
-template<> struct make_unsigned<signed long long>      { typedef unsigned long long type; };
-template<> struct make_unsigned<unsigned long long>    { typedef unsigned long long type; };
 #if EIGEN_COMP_MSVC
 template<> struct make_unsigned<signed __int64>   { typedef unsigned __int64 type; };
 template<> struct make_unsigned<unsigned __int64> { typedef unsigned __int64 type; };
 #endif
 
-// Some platforms define int64_t as long long even for C++03. In this case we
-// are missing the definition for make_unsigned. If we just define it, we get
-// duplicated definitions for platforms defining int64_t as signed long for
-// C++03. We therefore add the specialization for C++03 long long for these
-// platforms only.
-#if EIGEN_OS_MAC
+// Some platforms define int64_t as `long long` even for C++03, where
+// `long long` is not guaranteed by the standard. In this case we are missing
+// the definition for make_unsigned. If we just define it, we run into issues
+// where `long long` doesn't exist in some compilers for C++03. We therefore add
+// the specialization for these platforms only.
+#if EIGEN_OS_MAC || EIGEN_COMP_MINGW
 template<> struct make_unsigned<unsigned long long> { typedef unsigned long long type; };
 template<> struct make_unsigned<long long>          { typedef unsigned long long type; };
 #endif