configure: add -no-undefined to LDFLAGS on OS/2

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
Fixing missing <inttypes.h> include

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
Use calloc instead of malloc+memset
Do not reinvent strdup

Fixes builds for Hurd...
Do not crash on calling vm_close with NULL param
dvdnav_read_cache_new: invert a condition
dvdnav_read_cache_clear: use calloc instead of malloc
dvdnav_open: factorize the error path

And fail in new error cases
Fix memleak
Ignore all generated libtool helper files and release tarballs

Also add explicit path to ignored generated files.