[gdal-dev] Add capability to safely link against an external libtiff (3.X) and a GDAL build with internal libtiff (4.0) support

[Even Rouault]

> Do you have some particular indication about how to test it?
> Which test programs did you use?

My tests mainly consisted in checking that GDAL would compile and link 
successfully with various combinations of the configure options.

With the renaming options enabled, I did a "objdump -t libgdal.so | awk 
'{print $6}' | grep TIFF | grep -v TIFFjpeg_ | grep -v aig_ | grep -v gdal_ | 
sort -u" to ensure that all the symbols that should be renamed are. You will 
notice a few remaining occurrences but I think they are safe.

Also, when the renaming options where enabled, I added -ltiff -lgeotiff to the 
gdalinfo linking line, before or after -lgdal, and tested the executable on a 
few files.

> 
> 
> It seems to me that people of the the OTB project had serious problems
> with this issue in the past and they have a fantastic test framework.
> 
> Maybe we could also ask to them for a little help for testing.

Yes indeed, I had CC'ed Julien Malik who is affiliated with the OTB project in 
my announcement email.

> 
> 
> ciao