Dear list, I am trying to cross-compile ginac for windows. To do this I am using M Cross Environment (see www.mxe.cc for more info) to cross-compile ginac from windows. MXE automatically creates a cross-compilation environment for you that integrates with autotools, cmak or normal makefiles. Using MXE I successfully built the CLN library from the w64 branch of this git repository: https://github.com/jrheinlaender/cln/tree/w64 Now I am trying to build ginac itself, but am getting the following error: /bin/bash ../libtool --tag=CXX --mode=compile x86_64-w64-mingw32.static-g++ -std=gnu++11 -DHAVE_CONFIG_H -I. -I../config -DLIBEXECDIR='"/opt/mxe/usr/x86_64-w64-mingw32.static/libexec/"' -std=c++11 -MT libginac_la-fderivative.lo -MD -MP -MF .deps/libginac_la-fderivative.Tpo -c -o libginac_la-fderivative.lo `test -f 'fderivative.cpp' || echo './'`fderivative.cpp libtool: compile: x86_64-w64-mingw32.static-g++ -std=gnu++11 -DHAVE_CONFIG_H -I. -I../config -DLIBEXECDIR=\"/opt/mxe/usr/x86_64-w64-mingw32.static/libexec/\" -std=c++11 -MT libginac_la-fderivative.lo -MD -MP -MF .deps/libginac_la-fderivative.Tpo -c fderivative.cpp -DDLL_EXPORT -DPIC -o .libs/libginac_la-fderivative.o factor.cpp: In function 'GiNaC::ex GiNaC::{anonymous}::factor_multivariate(const GiNaC::ex&, const exset&)': factor.cpp:2254:56: error: conversion from 'long long unsigned int' to 'GiNaC::numeric' is ambiguous numeric modulus = (vnlst.nops() > 3) ? vnlst.nops() : 3; ^ In file included from factor.cpp:58:0: numeric.h:94:2: note: candidate: GiNaC::numeric::numeric(double) numeric(double d); ^ numeric.h:92:2: note: candidate: GiNaC::numeric::numeric(long unsigned int) numeric(unsigned long i); ^ numeric.h:91:2: note: candidate: GiNaC::numeric::numeric(long int) numeric(long i); ^ numeric.h:90:2: note: candidate: GiNaC::numeric::numeric(unsigned int) numeric(unsigned int i); ^ numeric.h:89:2: note: candidate: GiNaC::numeric::numeric(int) numeric(int i); ^ This is from the master barnch of the git repository, but I get the same error using the latest release. Is there likely to be an easy fix, or is my quest in vain? If you are interested at all, I built CLN using MXE like this: autoreconf -iv ./configure --host=x86_64-w64-mingw32.static CXXFLAGS="$CXXFLAGS -std=c++11" --prefix=/opt/mxe/usr/x86_64-w64-mingw32.static make -j3 make install However, I should mention that I also manually removed the subdirectories tests, examples, doc and benchmarks from the Makefile.am and configure.ac before building. I then tried to build ginac the exact same way: autoreconf -i ./configure --host=x86_64-w64-mingw32.static CXXFLAGS="$CXXFLAGS -std=c++11" --prefix=/opt/mxe/usr/x86_64-w64-mingw32.static make -j3 make install Regards, Richard