libc/time: Migrate to upstream musl

Migrate all identical files under libc/time to upstream musl.

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
libc/temp: Migrate to upstream musl

Migrate all identical files under libc/temp to upstream musl.

Reviewed-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
libc/network: Migrate to upstream musl

Migrate all identical files under libc/network to upstream musl.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
musl: clean more files from libc/stdio

A few files only added "#define _GNU_SOURCE" to the original musl code,
supposedly to make this work together with glibc headers. Since we no
longer use glibc headers in our compilation (and haven't done so in a
very long time), this different is no longer relevant, and can be dropped.

Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
libc: add the new memory files to the build

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>