Compiling ECW support on Linux fails

[rst]

The ECW SDK ecw_jpeg_2000_sdk_3_3_source.zip / libecwj2-3.3 seems to require two compiler defs to succeed:

-DPOSIX -DLINUX

Fedora release 8 (Werewolf) 2.6.21.7-2.fc8xen x86_64 gcc 4.1.2 20070925 (Red Hat 4.1.2-33) GDAL gdalsvn-trunk-20091012

[Even Rouault]

This does not look like a GDAL issue, so I close it for the same reasons as in #3162. You might want to mention your findings in http://trac.osgeo.org/gdal/wiki/ECW however.

[rst]

Sorry, seems I wasn't clear enough - it should read 'compiling GDAL with ECW support requires the extra defs to succeed'.

I think the configure should add the defs in GDALmake.opt - output being like this:

CPPFLAGS = -D_REENTRANT -I$(GDAL_ROOT)/port -I/mnt/sdi/GDAL/libecwj2-3.3/include -DLINUX -DPOSIX

[warmerdam]

I've actually taken to embedding extra flags in NCSTypes.h in my local copy of 3.3 rather than cludging up the GDAL build and configuration code. I have added a note about this issue in the ECW building wiki page.