Alexander Ziegler / gammalib

The export of MACOSX_DEPLOYMENT_TARGET led to some problems when trying to compile GammaLib on Mac OS X using the MacPorts gcc 4.4 compiler. The problems were uncatched exceptions that occured in some of the unit tests. After some debugging I discovered (by chance) that commenting the export of MACOSX_DEPLOYMENT_TARGET solved the problem.

Going into the Apple documentation (http://developer.apple.com/library/mac/#technotes/tn2064/_index.html) it appears that weak linking could be the root cause of the problems. With the current configuration on the Mac OS X 10.6 system on which the tests were done, MACOSX_DEPLOYMENT_TARGET=10.4. Following Apple's documentation, weak linking is implement from Mac OS X 10.2 on. Not specifying MACOSX_DEPLOYMENT_TARGET will automatically set the version to 10.1, hence no weak linking will be used.

Although I'm not 100% sure that weak linking indeed was the issue, removing the export of MACOSX_DEPLOYMENT_TARGET also removed the problems. I thus moved the export of MACOSX_DEPLOYMENT_TARGET into the --enable-universalsdk block, i.e. the export will only be done of the --enable-universalsdk option is selected. It remains to be seen whether this is the wanted behaviour.

The Apple gcc compiler requires the gomp_thread_attr global to be
defined when OpenMP functions are called without having any OpenMP
section in the code. This specific requirement is now detected in
the configure script using some dedicated test code, and the compile
definition HAVE_OPENMP_DARWIN_KLUGE is set that allows inclusion of
the appropriate code when needed.

Furthermore, the OPENMP_LIB_LDFLAGS is not set to -lgomp on Darwin
anymore as this appears not to be needed.

The swig files are needed for building of the ctools bindings, hence we put back the distribution of these files.

Summarize bug fix changes.