Building LibVNCServer-0.6 for m68k-rtems

Mark Mussetter mark at
Wed Aug 18 14:08:50 UTC 2004

Thank you for the explanation.  It's making more sense to me now.

At 12:01 AM 8/18/2004, you wrote:
>On Tue, 2004-08-17 at 19:10, Mark Mussetter wrote:
> > I have some questions about building LibVNCServer-0.6 for RTEMS.  I'm not
> > very experienced with makefiles or configure so these questions might be
> > pretty basic.
> >
> > Our system:
> > target = Motorola Coldfire 5272
> > host = Cygwin (running on a Windows XP machine)
> >
> > My questions are in regards to the --host, --target, and --build 
> options to
> > configure.
> >
> > I would assume that to get LibVNCServer to build a library that I could
> > link in to my RTEMS application, I would need to specify
> > --target=m68k-rtems.
> >   However, when I do this, configure finds and invokes
> > the standard gcc compiler from my usr/bin directory in the Cygwin tree.
>Make sure to have the path to your compiler in $PATH (e.g. 
>and try
>configure --host=m68k-rtems
> > I have tried all of the combinations of --build, --host, and --target
> > options and it seems that the only way I can get configure to find and use
> > the m68k-rtems compiler to build LibVNCServer is if I specify
> > "--host=m68k-rtems" on the command line to ./configure.
> > It doesn't seem right to me to specify the --host variable.
>No, this is correct.
>--build ... system you are building on (Normally, automatically guessed,
>rarely needed to be specified manually.); e.g. i686-pc-linux-gnu or
>--host ... system you are building binaries for (the system they are
>supposed to run on), here: m68k-rtems
>--target ... system the binaries to build are supposed to generate code
>for (Normally only required by cross-tools).
>I.e. configure --build=i686-pc-linux-gnu \
>--host=i686-pc-cygwin --target=m68-rtems
>is supposed to configure a package for building on i686-pc-linux-gnu,
>generate binaries to run on i686-pc-cygwin, which produce output for
>[Cross building a cygwin->m68-rtems tool-package on linux]
>What might confuse you is binutils, gdb, GCC and RTEMS using a sightly
>different convention for their top level configure scripts and the
>general recommendation to use "--target=..." for cross-compilation.
>Somewhat oversimplifying, this is mostly a historical relic only being
>used in toplevel configure scripts of complex packages and a side-effect
>of complex defaulting rules being applied to --build, --host, --target.
> > Can anyone tell me how I need to set the --host, --build, and --target 
> options?
>In general, you need to examine how a package processes them.
>In case of simple packages, using one autoconf-2.5x generated configure
>script (such as LibVNCserver), it is always --host.
>In case of complex packages (Several subpackages, several configure
>scripts) things can be different.
>However, internally, autoconf-2.5x-based configure scripts of
>subpackages apply the autoconf-2.5x canonicalization rules.
>E.g. RTEMS consists of several subpackages, all of them apply
>autoconf-2.5x and all of them internally apply "--host=..."

Mark Mussetter
Link Communications, Inc.
1035 Cerise Rd
Billings, MT 59101-7378
phone: (406) 245-5002 ext 105
Fax:    (406) 245-4889
MailTo:mark at

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