Recompiling grass with gcc 4.9.3, I see this error message: c++ -I/var/tmp/portage/sci-geosciences/grass-6.4.2/work/grass-6.4.2/dist.x86_64-pc-linux-gnu/include -march=amdfam10 -O2 -ggdb -pipe -D_FILE_OFFSET_BITS=64 -DPACKAGE=\""grasslibs"\" -I/var/tmp/portage/sci-geosciences/grass-6.4.2/work/grass-6.4.2/dist.x86_64-pc-linux-gnu/include -o OBJ.x86_64-pc-linux-gnu/mm.o -c mm.cc In file included from ami_stream.cc:29:0: /var/tmp/portage/sci-geosciences/grass-6.4.2/work/grass-6.4.2/dist.x86_64-pc-linux-gnu/include/grass/iostream/ami_stream.h:252:48: error: redeclaration of ‘AMI_STREAM<T>::AMI_STREAM(const char*, AMI_stream_type)’ may not have default arguments [-fpermissive] AMI_stream_type st = AMI_READ_WRITE_STREAM) { ^ /var/tmp/portage/sci-geosciences/grass-6.4.2/work/grass-6.4.2/dist.x86_64-pc-linux-gnu/include/grass/iostream/ami_stream.h:549:71: error: redeclaration of ‘AMI_err AMI_STREAM<T>::read_array(T*, off_t, off_t*)’ may not have default arguments [-fpermissive] AMI_err AMI_STREAM<T>::read_array(T *data, off_t len, off_t *lenp=NULL) { ^ This looks like an issue which has already been addressed upstream. See https://trac.osgeo.org/grass/changeset/52130 and https://trac.osgeo.org/grass/ticket/1676. I suggest we include that fix in the grass patchset, or bump grass to a version which includes that fix. The latest 6.x is 6.4.5, while the current stable is 7.0.0.
There is a second, similar issue: /var/tmp/portage/sci-geosciences/grass-6.4.2/work/grass-6.4.2/dist.x86_64-pc-lin ux-gnu/include/grass/iostream/embuffer.h:1123:61: error: redeclaration of ‘long int em_buffer<T, Key>::insert(AMI_STREAM<T>*, long int)’ may not have default ar guments [-fpermissive] long em_buffer<T,Key>::insert(AMI_STREAM<T>* str, long bos=0) { ^ https://trac.osgeo.org/grass/changeset/53077 https://trac.osgeo.org/grass/ticket/1714
Please attach emerge --info and the full build log.
Closing as OBSOLETE - sci-geosciences/grass-7.0.1 has been added to the tree as per bug 514514 and subsequently revbumped. Note that sci-geosciences/grass:6 has been masked and will be removed from the tree in the coming weeks.