Use exit(EXIT_FAILURE) instead of g_error() (which calls abort(), possibly
causing a core dump) in fastafetch.c & fastaremove.c to pass regression
tests. Should do this in other places as well...
Instead of home-grown GAM_get_tmp_file_handler(), simply use tmpfile().
Fixed bug in codegen.c:Codegen_get_code_dir() where the pointer returned
by getenv() could be inadvertently freed.
Replace deprecated glib functions g_strup() & g_strdown() with home-grown
strup() & strdown().