[musl] Remove LFS64 and _LARGEFILE64_SOURCE definitions

This was reverted previously as dart was using some of these
definitions. Dart has since been changed.

Test: full build, plus grep

Change-Id: Ibce5d9873b6132e5099370a5be7ddd54e7009aa2

[musl] Reintroduce LFS64 definitions

This partially reverts commit
e831a8265b4c3954eb78782c24ce5257520255b2.

These are currently used by the dart runtime. Once it is patched not
to do so, they will be removed again.

Test: built upper layers, including dart

Change-Id: I8261dd44c3ff0ceb067395afe76cb80f4c6f5a8e

[musl] Remove LFS64 definitions

Test: dash was the only client, and the shell still works

Change-Id: Ib5c2b99634b7b3545ef621096fe33663aadfb99f

[fs] Use the Fuchsia-defined open flags

Re-lands 2aff2cba029cf0f7e98e6d19f6dc7a663c318227

This change uses the Fuchsia-defined flags on the wire
as well as on filesystem servers. Clients interacting
with filesystems through the POSIX compatibility layer
can continue using POSIX open flags; they will be translated
by the RIO layers client-side.

ZX-1359 #comment In Progress

Change-Id: I4972c024547a0daa2146831e49e34d3ef905d4b4

Revert "[fs] Use the Fuchsia-defined open flags"

This reverts commit 2aff2cba029cf0f7e98e6d19f6dc7a663c318227.

Reason for revert: Fuchsia uses upstream Rust, which doesn't pull these constants from our C library, but their own. I'll need to wait a few days for us to update upstream Rust before we can make progress here.

Original change's description:
> [fs] Use the Fuchsia-defined open flags
>
> This change uses the Fuchsia-defined flags on the wire
> as well as on filesystem servers. Clients interacting
> with filesystems through the POSIX compatibility layer
> can continue using POSIX open flags; they will be translated
> by the RIO layers client-side.
>
> ZX-1359 #comment In Progress
>
> Change-Id: I27dfdea2024183d5d59daa1ed7d8886d89d503d0

TBR=kulakowski@google.com,smklein@google.com,swetland@google.com,mcgrathr@google.com,planders@google.com

Change-Id: If93c2da36f92ea28ed013a61c01c6ec521da26cc
No-Presubmit: true
No-Tree-Checks: true
No-Try: true

[fs] Use the Fuchsia-defined open flags

This change uses the Fuchsia-defined flags on the wire
as well as on filesystem servers. Clients interacting
with filesystems through the POSIX compatibility layer
can continue using POSIX open flags; they will be translated
by the RIO layers client-side.

ZX-1359 #comment In Progress

Change-Id: I27dfdea2024183d5d59daa1ed7d8886d89d503d0

[mxio][fs][remoteio] allow pipelined open()

Pull the pipeline flag into fcntl.h as O_PIPELINE to make it visible
to posix API consumers. Adjust mxio and fs implementations to use
this instead of the old remoteio constant. Use the same numeric
value to preserve wire format compatibility.

Allow O_PIPELINE to be passed to open() and cause a pipelined open
which will succeed as long as the message can be written, but will
result in failure (for unknown reason) when you attempt IO against
that object if the open was rejected.

Change-Id: I2a5be2a3cb99da16f9ab7662de9e98801dbf71cc

[fs] Add support for O_ADMIN, restricting unmounting capability

O_ADMIN is a new flag which is provided to connections to
new filesystems. This flag indicates that the client which
has the iostate connection has the capability to demand that
the filesystem should shut down. Previously, ANY open connection
to a filesystem (file, directory, etc) would be sufficient to
terminate the entire filesystem. With the addition of the
O_ADMIN flag, however, unmounting capability is restricted to
the connection that is typically pinned to the mounting vnode.

Test added in fs-management, blobstore tests updated (connections
to single blobs can no longer unmount the blobstore).

Change-Id: Ib371f10e6ddd446ebc25ec513a3d7c1863eca30a

[musl] Add O_NOREMOTE flag to open flags

This flag will signal for the open operating to access the filesystem
which is hosting a remote point, rather than the filesystem which is
being hosted.

Change-Id: Id8d487391d7b2c62436a806068f49098218b1c40

[musl] Unify fcntl between architectures

All values taken from generic/fcntl.h, other than F_GETLK, F_SETLK, and
F_SETLKW, which were taken from x86_64.

The unification of fcntl will make it easier to manipulate flags
without risking collision on different machines.

This patch only relocates "$ARCH/fcntl.h" to "fcntl.h". It does not
remove or otherwise modify values.

Change-Id: I293ef627794a5422aa1c1cb1864478abd518a0ad

[musl] Use #pragma once in musl's public headers

Like the prior commit, this only replaces existing ifdef guards.

Change-Id: I39be129111db9f129aef72a53f986ce6a49376ac

[magenta] Initial commit