FreeBSD crossbuild with GCC on Linux host

Dockerfile

FROM ubuntu:latest
RUN apt-get update

# install dependencies
RUN apt-get install --yes gcc g++ bison make wget xz-utils

# Compile binutils
RUN mkdir /build && cd /build && \
  wget https://ftp.gnu.org/gnu/binutils/binutils-2.29.tar.xz && \
  tar -xf binutils-2.29.tar.xz && cd binutils-2.29 && \
  ./configure --enable-libssp --enable-gold --enable-ld \
      --target=x86_64-pc-freebsd10 --prefix=/opt/cross-freebsd && make -j4 && \
  make install && \
  rm -rf /build && mkdir /build

# Get FreeBSD libs/headers, extract and fix broken links
RUN cd /build/ && \
  wget http://ftp.plusline.de/FreeBSD/releases/amd64/10.4-RELEASE/base.txz && \
  cd /opt/cross-freebsd/x86_64-pc-freebsd10 && \
  tar -xf /build/base.txz ./lib/ ./usr/lib/ ./usr/include/ && \
  cd /opt/cross-freebsd/x86_64-pc-freebsd10/usr/lib && \
  find . -xtype l|xargs ls -l|grep ' /lib/' \
    | awk '{print "ln -sf /opt/cross-freebsd/x86_64-pc-freebsd10"$11 " " $9}' \
    | /bin/sh && \
  rm -rf /build && mkdir /build

# Compile GMP
RUN cd /build && \
  wget https://ftp.gnu.org/gnu/gmp/gmp-6.1.2.tar.xz && \
  tar -xf gmp-6.1.2.tar.xz && \
  cd gmp-6.1.2 && \
  ./configure --prefix=/opt/cross-freebsd --enable-shared --enable-static \
      --enable-fft --enable-cxx --host=x86_64-pc-freebsd10 && \
  make -j4 && make install && \
  rm -rf /build && mkdir /build

# Compile MPFR
RUN cd /build && \
  wget https://ftp.gnu.org/gnu/mpfr/mpfr-3.1.6.tar.xz && tar -xf mpfr-3.1.6.tar.xz && \
  cd mpfr-3.1.6 && \
  ./configure --prefix=/opt/cross-freebsd --with-gnu-ld  --enable-static \
      --enable-shared --with-gmp=/opt/cross-freebsd --host=x86_64-pc-freebsd10 && \
  make -j4 && make install && \
  rm -rf /build && mkdir /build

# Compile MPC
RUN cd /build && \
  wget https://ftp.gnu.org/gnu/mpc/mpc-1.0.3.tar.gz  && tar -xf mpc-1.0.3.tar.gz && \
  cd mpc-1.0.3 && \
  ./configure --prefix=/opt/cross-freebsd --with-gnu-ld --enable-static \
      --enable-shared --with-gmp=/opt/cross-freebsd \
      --with-mpfr=/opt/cross-freebsd --host=x86_64-pc-freebsd10 && \
  make -j4 && make install && \
  rm -rf /build && mkdir /build

# 1. Configure GCC
# 2. Fix GCC for the failed aligned_alloc detection
# 3. Build and install
RUN cd /build && \
  wget https://ftp.gnu.org/gnu/gcc/gcc-7.2.0/gcc-7.2.0.tar.xz && \
  tar xf gcc-7.2.0.tar.xz && \
  cd gcc-7.2.0 && mkdir build && cd build && \
  ../configure --without-headers --with-gnu-as --with-gnu-ld --disable-nls \
      --enable-languages=c,c++ --enable-libssp --enable-gold --enable-ld \
      --disable-libitm --disable-libquadmath --target=x86_64-pc-freebsd10 \
      --prefix=/opt/cross-freebsd --with-gmp=/opt/cross-freebsd \
      --with-mpc=/opt/cross-freebsd --with-mpfr=/opt/cross-freebsd --disable-libgomp \
      --with-sysroot=/opt/cross-freebsd/x86_64-pc-freebsd10  \
      --with-build-sysroot=/opt/cross-freebsd/x86_64-pc-freebsd10 && \
  cd /build/gcc-7.2.0 && \
  echo '#define HAVE_ALIGNED_ALLOC 1' >> libstdc++-v3/config.h.in && \
  cd /build/gcc-7.2.0/build && \
  make -j4 && make install && \
  rm -rf /build
  
  ## Configure run
  ## ./configure CC=/opt/cross-freebsd/bin/x86_64-pc-freebsd10-gcc CXX=/opt/cross-freebsd/bin/x86_64-pc-freebsd10-g++ \
  ## --host=x86_64-pc-freebsd10 LDFLAGS="-nodefaultlibs -lc++ -lm -lc -lgcc_s -lgcc" \
  ## CXXFLAGS="-std=c++11 -I/opt/cross-freebsd/x86_64-pc-freebsd10/usr/include/c++/v1 -nostdinc++"

Any interest in publishing the image to Docker Hub?

https://github.com/mcandre/snek/blob/master/docker/freebsd/Dockerfile

https://hub.docker.com/layers/167700801/mcandre/snek/freebsd/images/sha256-6b5e5c796dd46aa10ba10606c08e7fadbbef86d46427572ab99849474187e723?context=repo