How to build Universal Binary versions of Coin and SoQt
=======================================================

Basically, the procedure is as simple as adding the --enable-universal
configure option. So e.g. for a Universal Binary debug build of
Coin, you would configure Coin as

        Coin-2.x.x/configure --enable-debug --enable-universal

However, there are a number of things you should keep in mind. Please
read the following carefully, it might (and will) save you some
headaches when things don't work as they should:


All or Nothing
--------------

In order to be able to create Universal Binaries, all libraries and
frameworks that you link against must also be Universal. So e.g. to be
able to create a UB version of SoQt, you'll also need a UB version of
Coin -- and of Qt.


Sc21
----

To build the UB version of Sc21, do the usual Xcode magick.
Specifically, this means 

  - bring up the Project Info dialog (Project -> Edit Project
    Settings)
  - choose the Build tab
  - change the Architectures setting from $(NATIE_ARCH) to 
    "ppc i386".
  - rebuild

If you are doing this on a PowerPC machine, you also need to do the
following step:

  - choose the "General" tab
  - select "Mac OS 10.4 (Universal) for the "Cross-Develope Using
    Target SDK" setting
  - create symbolik links for Inventor.framework and Sc21.framework
    in the UB SDK (see next section)


Creating Universal Binaries on PPC
----------------------------------

To create UBs on a PPC machine, the Universal Binary SDK needs to be
specified by passing the -isysroot option to gcc. This is taken care
of by our configure script, however there is one small issue: As this
option changes the root directory of where system libraries and
frameworks are expected to reside, any frameworks located in
/Library/Frameworks will not be found!

Consider this scenario:

  - You configure Coin as a Universal Binary, using the --enable-universal
    configure flag.

  - This flag causes "-isysroot /Developer/SDKs/MacOSX10.4u.sdk" to be
    added to the CFLAGS variable, which means that the instead of
    /System/Library/Frameworks/OpenGL.framework, the path 
    /Developer/SDKs/MacOSX10.4u.sdk/System/Library/Frameworks/OpenGL.framework
    will be used instead. This is intentional, and alright.

  - Everything goes well, Coin ends up being installed in
    /Library/Frameworks/Inventor.framework

  - You configure SoQt as a Universal Binary, using the --enable-universal
    configure flag.

  - This flag causes "-isysroot /Developer/SDKs/MacOSX10.4u.sdk" to be
    added to the CFLAGS variable, which means that the instead of
    /System/Library/Frameworks/OpenGL.framework, the system looks for
    /Developer/SDKs/MacOSX10.4u.sdk/System/Library/Frameworks/OpenGL.framework
    instead. This is intentional, and alright.

  - However, it also means that instead of      
    /Library/Frameworks/Inventor.framework, the system looks for
    /Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks/Inventor.framework
    instead. This is obviously problem.

The solution is simple: Create a symbolic link in the 10.4u SDK...

    sudo mkdir -p /Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks
    sudo ln -s /Library/Frameworks/Inventor.framework \
               /Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks/

... after installing Coin (but before running SoQt-configure).

If you are using the framework installation of Qt-4, you will need to
do the same for the Qt frameworks. Something like this should do the
trick:

  cd /Library/Frameworks
  for i in Qt*.framework; do sudo ln -s /Library/Frameworks/$i \
  /Developer/SDKs/MacOSX10.4u.sdk/Library/Frameworks/ ; done