RE: Compiling apps to Mingw32 with cygwin

["Jon Leichter" <jon@symas.com>]

Earnie Boyd wrote:
> Your wrapper script is a good idea but has the wrong name as has been
> pointed out already.  It needs to be named i386-pc-mingw32-gcc and a
> copy as mingw32-gcc so that when specifying the --host=mingw32 or
> --host=i386-pc-mingw32 the configure script will find it appropriately.
> Of course to do this you also need to do the same for the binutils
> binaries.
>
> Yes, specifying --host without the other parts of the triplet indicates
> a cross build to configure.  You are even warned of this fact.  Specify
> all three to avoid configure from figuring it out on it's own.  You've
> just been lucky enough to not configure a package that cares.  Try
> configuring binutils if you want to see what happens with just
> specifying host.

J. Henning Schwentner wrote:
> Dear Earnie,
>
> I do not get it with the --build switch. Am I not building on
> i686-pc-cygwin? Is it i368-pc-mingw because I use the mingw-headers?
> But I use the cygwin-compiler.
>
> Sorry, but I am confused a bit ...

Earnie, I'm confused too.

The symlink approach (i.e. i386-pc-mingw32-gcc) might be appropriate for
latter versions of autoconf, but it does not work for earlier versions. I
contribute to the OpenLDAP project, specifically its MinGW support. To build
MinGW OpenLDAP, I've also got to build regex-0.12, gdbm-1.8.0, and
libtool-1.4.2. As far as I can tell, none of the configure scripts in these
projects conform to the notion of looking for ${host}-gcc or any other
${host}-tool. In these projects, the solution I pointed out works
flawlessly:

	CC=mgcc ./configure --host=i686-pc-mingw32

The configure script in regex-0.12 does not even accept the --host switch
(or --target or --build). Instead, it treats the last parameter on the
command line as the "host":

	CC=mgcc ./configure i686-pc-mingw32

The configure script in regex-0.12 does not make any real use of this value,
so it doesn't really have any effect on the build.

I originally responded to J. Henning Schwentner, who started this thread. At
this point, I don't remember what he said he was building. However, it's
obvious to me that unless you're building a project with a configure script
built by an up-to-date version of autoconf, none of what you have suggested
will work. Note that the approach I suggested will work in either case, WITH
THE POSSIBLE EXCEPTION (as you have stated) that one runs into trouble
if --build and --target are not specified as well.

This spawns another associated topic. What are the right values for the
triplets (in CURRENT autoconf)? If you're building MinGW binaries in a
Cygwin-hosted environment, it seems to me that you should ONLY
specify --target=i686-pc-mingw32 and let the other two switches resolve
themselves to i686-pc-cygwin. When I build MinGW binaries with Cygwin tools,
I am not using a MinGW-hosted environment or MinGW tools. All of binutils,
for example, are still Cygwin tools, and they DON'T honor the -mno-cygwin
switch. I don't want to symlink those tools either. None of this should
matter as long as GCC produces MinGW binaries. Why should it matter if
configure believes that you're doing a cross-compile. In a loose sense, you
are. This, of course, is a religious argument.

Note that I have tried to only use the --target switch in my projects,
opposed to the --host switch. However, in OpenLDAP and the other related
projects, NONE of the configure scripts handle these switches correctly. I
found that using --host was the best solution for these projects.

Indeed, until the latest version of autoconf makes its way into all projects
as a standard, these switches will need to be examined by the project
builder in order to have context on how to build.

Jon


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