toolchain: binutils: add support for version 2.38

While at it, also fix the download.xs4all.nl and add ftp.gnu.org to the GNU
mirrors, as it seems to be updated faster.

Deleted (upstreamed):
600-Close_the_file_descriptor.patch [1]

[1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=5a98fb7513b559e20dfebdbaa2a471afda3b4742



Signed-off-by: Rui Salvaterra <rsalvaterra@gmail.com>