Remove dependencies on xwin and zig.  We're not offering cross-compilation
options using these crates.

diff --git a/Cargo.toml b/Cargo.toml
index 6cbdca3..22ea5ef 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -76,16 +76,6 @@ version = "0.1.4"
 [dependencies.cargo-options]
 version = "0.6.0"
 
-[dependencies.cargo-xwin]
-version = "0.14.3"
-optional = true
-default-features = false
-
-[dependencies.cargo-zigbuild]
-version = "0.16.10"
-optional = true
-default-features = false
-
 [dependencies.cargo_metadata]
 version = "0.15.3"
 
@@ -310,8 +300,6 @@ version = "4.3.0"
 [features]
 cli-completion = ["dep:clap_complete_command"]
 cross-compile = [
-    "zig",
-    "xwin",
 ]
 default = [
     "full",
@@ -330,7 +318,6 @@ log = ["tracing-subscriber"]
 native-tls = [
     "dep:native-tls",
     "ureq?/native-tls",
-    "cargo-xwin?/native-tls",
     "dep:rustls-pemfile",
 ]
 password-storage = [
@@ -340,7 +327,6 @@ password-storage = [
 rustls = [
     "dep:rustls",
     "ureq?/tls",
-    "cargo-xwin?/rustls-tls",
     "dep:rustls-pemfile",
 ]
 scaffolding = [
@@ -358,5 +344,3 @@ upload = [
     "wild",
     "dep:dirs",
 ]
-xwin = ["cargo-xwin"]
-zig = ["cargo-zigbuild"]
m'>log</a><a href='/guix/tree/tests/nar.scm?id=f97176e78cbdc891225440ebee577f1da792c78c'>tree</a><a href='/guix/commit/tests/nar.scm?id=f97176e78cbdc891225440ebee577f1da792c78c'>commit</a><a href='/guix/diff/tests/nar.scm?id=f97176e78cbdc891225440ebee577f1da792c78c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/nar.scm'>
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<div class='path'>path: <a href='/guix/log/?id=f97176e78cbdc891225440ebee577f1da792c78c'>root</a>/<a href='/guix/log/tests?id=f97176e78cbdc891225440ebee577f1da792c78c'>tests</a>/<a href='/guix/log/tests/nar.scm?id=f97176e78cbdc891225440ebee577f1da792c78c'>nar.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/nar.scm?id=f97176e78cbdc891225440ebee577f1da792c78c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-12-15 17:32:09 +0100'>2020-12-15</span></td><td><a href='/guix/commit/tests/nar.scm?id=2718c29c3fb9f9de2ec897248ad49ae11ca39b7a'>nar: Deduplicate files right as they are restored.</a><span class='msg-avail'>...<span class='msg-tooltip'>This avoids having to traverse and re-read the files that we have just
restored, thereby reducing I/O.

* guix/serialization.scm (dump-file): New procedure.
(restore-file): Add #:dump-file parameter and honor it.
* guix/store/deduplication.scm (tee, dump-file/deduplicate): New
procedures.
* guix/nar.scm (restore-one-item): Pass #:dump-file to 'restore-file'.
(finalize-store-file): Pass #:deduplicate? #f to 'register-items'.
* tests/nar.scm &lt;top level&gt;: Call 'setenv' to set "NIX_STORE".
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-12-15 17:32:09 +0100'>2020-12-15</span></td><td><a href='/guix/commit/tests/nar.scm?id=ed7d02f7c198970ce3fe94bcee47592963326446'>serialization: 'restore-file' sets canonical timestamp and permissions.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/serialization.scm (restore-file): Set the permissions and mtime
of FILE.
* guix/nar.scm (finalize-store-file): Pass #:reset-timestamps? #f to
'register-items'.
* tests/nar.scm (rm-rf): Add 'chmod' calls to ensure files are writable.
("write-file + restore-file with symlinks"): Ensure every file in OUTPUT
passes 'canonical-file?'.
* tests/guix-archive.sh: Run "chmod -R +w" before "rm -rf".
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-12-15 17:32:09 +0100'>2020-12-15</span></td><td><a href='/guix/commit/tests/nar.scm?id=465d2cb286170933577de045e6e6dad7205bfe10'>serialization: 'fold-archive' notifies about directory processing completion.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/serialization.scm (fold-archive): Call PROC with a
'directory-complete tag when done with a directory.
(restore-file): Handle it.
* guix/scripts/archive.scm (list-contents): Likewise.
* guix/scripts/challenge.scm (archive-contents): Likewise.
* tests/nar.scm ("write-file-tree + fold-archive"): Adjust accordingly.
</span></span></td><td>Ludovic Courtès</td></tr>