Frank and others, due to an error in gdal/ogr/ogrsf_frmts/s57/GNUMakefile gdal-cvs won't compile if ogr is enabled. The solution is to add 's57featuredefns.o' to the 'OBJ =' line in the GNUMakefile in the s57 directory (and probably similar addition to the Makefile?). Cheers, Vincent.