Making a library MinGW compatible, general MinGW questions

[Christopher Thielen]

  Hi fedora-mingw,

I'm one of the developers on an open source game currently compiling on 
Linux, OS X and Windows. I'd like to set up Fedora cross-compile for the 
Windows binary; under MSYS/MinGW on Windows, all needed libraries and 
the game itself compile, so I'm hopeful it will be possible to do this 
without leaving Fedora.

I have a number of distinct problems in accomplishing this, mostly due 
to my lack of education with MinGW, so I'm hoping this is the correct 
list to seek help. I think it would be best if I start with some of the 
earliest issues I encountered in my build process, as they may affect or 
resolve later questions.

First, our software requires: libxml2, SDL, SDL_image, SDL_mixer and 
FTGL. SDL and libxml2 already have MinGW packages on Fedora and they 
worked very well. SDL_image and SDL_mixer did not but they compiled fine 
simply using mingw-configure, make, make install. Be that as it is, is 
there much else involved in package management for this sort of 
software? If not, I'd be interested in volunteering to maintain Fedora 
MinGW packages for SDL_image and SDL_mixer if they're not already on the 
way.

My first real spot of trouble came with FTGL, which uses the GNU 
autotools but seems to have some compatibility issues with MinGW. I 
understand this is a bug in FTGL, but I was hoping for advice on fixing 
this.

Their configure script fails to find OpenGL, attempting to link against 
-lGL. I understand for MinGW it's proper to link against -lopengl32 and 
add -mwindows to the compiler flags. Would the proper thing to do here 
be to add a check for the mingw system type in configure.ac and change 
the CFLAGS and LIBS to -lopengl32 instead of -lGL?

My apologies if this is such an elementary question but if I could learn 
more about this, I'd like to help ensure MinGW compatibility in more 
packages and in my own software.

Again, this is sort of the first of a small number of issues I ran into, 
but I'd like to take them one at a time instead of spamming the list 
with problems.

If this is not the proper list, I'd appreciate some advice on finding 
another.

Thank you,
Chris Thielen

[Erik van Pienbroek]

Hi Chris,

>  First, our software requires: libxml2, SDL, SDL_image, SDL_mixer and
>
>  FTGL. SDL and libxml2 already have MinGW packages on Fedora and they 
>  worked very well. SDL_image and SDL_mixer did not but they compiled fine 
>  simply using mingw-configure, make, make install. Be that as it is, is 
>  there much else involved in package management for this sort of 
>  software? If not, I'd be interested in volunteering to maintain Fedora 
>  MinGW packages for SDL_image and SDL_mixer if they're not already on the 
>  way. 
New mingw32 packages are always welcome! I don't know if you're already
familiar with maintaining regular RPMs for Fedora, but we tried to keep
the packaging of mingw32 packages as easy as possible. In order to port
a native Fedora package to a mingw32 package, there are some steps which
need to be done:

- Calls to the macro %configure need to be replaced with
%{_mingw32_configure}.
- File lists will need to be updated to use macro's like
%{_mingw32_bindir} and %{_mingw32_libdir} instead of %{_bindir} and
%{_libdir}
- The package needs to be made noarch, so a 'BuildArch: noarch' needs to
be added
- Some mingw32 specific BuildRequires need to be added. At least ones
should be added for mingw32-filesystem, mingw32-gcc and
mingw32-binutils. Depending on the dependencies of the package itself
more mingw32-specific BR's might be needed
- The top of the .spec file should begin with these set of macro's:
%global __strip %{_mingw32_strip}
%global __objdump %{_mingw32_objdump}
%global _use_internal_dependency_generator 0
%global __find_requires %{_mingw32_findrequires}
%global __find_provides %{_mingw32_findprovides}

When putting a new package up for review, don't forget to CC
fedora-mingw(a)lists.fedoraproject.org so that you have a better chance
that somebody reviews the package soon.

>  Their configure script fails to find OpenGL, attempting to link
> against 
>  -lGL. I understand for MinGW it's proper to link against -lopengl32 and 
>  add -mwindows to the compiler flags. Would the proper thing to do here 
>  be to add a check for the mingw system type in configure.ac and change 
>  the CFLAGS and LIBS to -lopengl32 instead of -lGL? 
The '-mwindows' compiler flag is used to indicate that the resulting
executable shouldn't show a console window when it's started. When the
compiler flag '-mconsole' is used a console window will be shown where
all stdout/stderr-output gets shown.

Applying a change in the configure.ac file which adds a special check
for mingw32 environments seems like the correct approach to me.

I don't know if the Windows opengl32 library contains all the OpenGL
functions you want to use, but there's also a mingw32-freeglut package
in the Fedora repositories which offers additional OpenGL functions.

If you've got any more questions, feel free to drop them on this list

Kind regards,

Erik van Pienbroek

[stefan riemens]

Please note that SDL_image and SDL_mixer are awaiting review at
https://bugzilla.redhat.com/show_bug.cgi?id=543154 and
https://bugzilla.redhat.com/show_bug.cgi?id=543147). It would be great
if you could a (informal?) review.

Thanks,
Stefan (who needs to update those review requests...)

2010/9/25 Erik van Pienbroek <erik(a)vanpienbroek.nl&gt;
>  Hi Chris,
>
>  > First, our software requires: libxml2, SDL, SDL_image, SDL_mixer and
>  > FTGL. SDL and libxml2 already have MinGW packages on Fedora and they
>  > worked very well. SDL_image and SDL_mixer did not but they compiled fine
>  > simply using mingw-configure, make, make install. Be that as it is, is
>  > there much else involved in package management for this sort of
>  > software? If not, I'd be interested in volunteering to maintain Fedora
>  > MinGW packages for SDL_image and SDL_mixer if they're not already on the
>  > way.
>
>  New mingw32 packages are always welcome! I don't know if you're already
>  familiar with maintaining regular RPMs for Fedora, but we tried to keep
>  the packaging of mingw32 packages as easy as possible. In order to port
>  a native Fedora package to a mingw32 package, there are some steps which
>  need to be done:
>
>  - Calls to the macro %configure need to be replaced with
>  %{_mingw32_configure}.
>  - File lists will need to be updated to use macro's like
>  %{_mingw32_bindir} and %{_mingw32_libdir} instead of %{_bindir} and
>  %{_libdir}
>  - The package needs to be made noarch, so a 'BuildArch: noarch' needs to
>  be added
>  - Some mingw32 specific BuildRequires need to be added. At least ones
>  should be added for mingw32-filesystem, mingw32-gcc and
>  mingw32-binutils. Depending on the dependencies of the package itself
>  more mingw32-specific BR's might be needed
>  - The top of the .spec file should begin with these set of macro's:
>  %global __strip %{_mingw32_strip}
>  %global __objdump %{_mingw32_objdump}
>  %global _use_internal_dependency_generator 0
>  %global __find_requires %{_mingw32_findrequires}
>  %global __find_provides %{_mingw32_findprovides}
>
>  When putting a new package up for review, don't forget to CC
>  fedora-mingw(a)lists.fedoraproject.org so that you have a better chance
>  that somebody reviews the package soon.
>
>  > Their configure script fails to find OpenGL, attempting to link against
>  > -lGL. I understand for MinGW it's proper to link against -lopengl32 and
>  > add -mwindows to the compiler flags. Would the proper thing to do here
>  > be to add a check for the mingw system type in configure.ac and change
>  > the CFLAGS and LIBS to -lopengl32 instead of -lGL?
>
>  The '-mwindows' compiler flag is used to indicate that the resulting
>  executable shouldn't show a console window when it's started. When the
>  compiler flag '-mconsole' is used a console window will be shown where
>  all stdout/stderr-output gets shown.
>
>  Applying a change in the configure.ac file which adds a special check
>  for mingw32 environments seems like the correct approach to me.
>
>  I don't know if the Windows opengl32 library contains all the OpenGL
>  functions you want to use, but there's also a mingw32-freeglut package
>  in the Fedora repositories which offers additional OpenGL functions.
>
>  If you've got any more questions, feel free to drop them on this list
>
>  Kind regards,
>
>  Erik van Pienbroek
>
>
>  _______________________________________________
>  mingw mailing list
>  mingw(a)lists.fedoraproject.org
>  https://admin.fedoraproject.org/mailman/listinfo/mingw

[Richard W.M. Jones]

On Sat, Sep 25, 2010 at 01:03:39AM +0200, Erik van Pienbroek wrote:
>  In order to port a native Fedora package to a mingw32 package, there
>  are some steps which need to be done: 
[...]

Another good idea is to take a look at how existing packages are done.
Go to:

http://pkgs.fedoraproject.org/gitweb/?p=mingw32-glib2.git;a=tree

(replace mingw32-glib2 with other package names too)

and click on the .spec file.

>  When putting a new package up for review, don't forget to CC
>  fedora-mingw(a)lists.fedoraproject.org so that you have a better chance
>  that somebody reviews the package soon. 
See also:

http://join.fedoraproject.org/
http://fedoraproject.org/wiki/PackageMaintainers/Join

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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