Cross compiling from FreeBSD to Windows

David Yeske <dyeske@daemonnews.org>

This article explains how to cross compile from FreeBSD to Windows. This is possible because of the MinGW compiler which has been ported to FreeBSD and exists in the ports collection. We will use the PuTTY program, a gui ssh suite of utilities, as an example and cross compile it to run on windows. We will step you through modifying the existing FreeBSD ports framework to make this work. After the initial modification, other ports could be used to create windows binaries.

Cross compiling directions

This cookbook style guide will allow you to quickly begin cross compiling programs for windows.

• The first thing you need to do is install the mingw port. This is the compiler that creates the binaries that run on windows.

  # cd /usr/ports/devel/mingw32-gcc
  # make clean install
  

• Next, we install ccache. This will speed up the cross compilation.

  # cd /usr/ports/devel/ccache
  # make clean install
  

• Then we create a wrapper for ccache. This simple shell script will make it easier to compile using ccache. These two lines should be saved in the file /usr/local/mingw32/bin/ccache_cc Don't forget to use chmod to make it executable.

  #!/bin/sh
  exec ccache /usr/local/mingw32/bin/gcc "${@}"
  

• Now create a directory and place this Makefile in it. This Makefile is will work with the existing FreeBSD ports collection.
• In order for this Makefile to work, a modification must be made to the ports collection. The following code should be stored in a file called /usr/ports/Mk/bsd.win32.mk or the existing file /usr/ports/Mk/bsd.port.mk can be modified so the USE_WIN32=yes statement in the Makefile will cause the following to be defined, but that will take quite a bit more effort on your part to get right.

  BUILD_DEPENDS+= ${LOCALBASE}/mingw32/bin/gcc:${PORTSDIR}/devel/mingw32-gcc
  CC= ${LOCALBASE}/mingw32/bin/gcc
  CXX=    ${LOCALBASE}/mingw32/bin/g++
  DLLWRAP=${LOCALBASE}/mingw32/bin/dllwrap
  RANLIB= ${LOCALBASE}/mingw32/bin/ranlib
  WINDRES=${LOCALBASE}/mingw32/bin/windres
  

• Finally, you just need to compile PuTTY like a normal FreeBSD port. Do not run "make install", because it will not work.

  # cd putty
  # make CC=/usr/local/mingw32/bin/ccache_cc
  

Results

$ file *.exe
pageant.exe:  MS Windows PE 32-bit Intel 80386 GUI executable not relocatable
plink.exe:    MS Windows PE 32-bit Intel 80386 console executable not relocatable
pscp.exe:     MS Windows PE 32-bit Intel 80386 console executable not relocatable
psftp.exe:    MS Windows PE 32-bit Intel 80386 console executable not relocatable
putty.exe:    MS Windows PE 32-bit Intel 80386 GUI executable not relocatable
puttygen.exe: MS Windows PE 32-bit Intel 80386 GUI executable not relocatable
puttytel.exe: MS Windows PE 32-bit Intel 80386 GUI executable not relocatable


The resulting binarys can be run in Windows or under Wine.

Acknowledgments

I would like to thank the authors of MinGW and the various people that gave me feedback.


$Id: crosscompile,v 1.20 2004/09/09 05:58:18 www Exp $