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 6704e46..ff126a9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -83,16 +83,6 @@ version = "0.1.16"
 [dependencies.cargo-options]
 version = "0.7.2"
 
-[dependencies.cargo-xwin]
-version = "0.16.2"
-optional = true
-default-features = false
-
-[dependencies.cargo-zigbuild]
-version = "0.18.0"
-optional = true
-default-features = false
-
 [dependencies.cargo_metadata]
 version = "0.18.0"
 
@@ -321,8 +311,6 @@ version = "5.0.0"
 [features]
 cli-completion = ["dep:clap_complete_command"]
 cross-compile = [
-    "zig",
-    "xwin",
 ]
 default = [
     "full",
@@ -341,7 +329,6 @@ log = ["tracing-subscriber"]
 native-tls = [
     "dep:native-tls",
     "ureq?/native-tls",
-    "cargo-xwin?/native-tls",
     "dep:rustls-pemfile",
 ]
 password-storage = [
@@ -351,7 +338,6 @@ password-storage = [
 rustls = [
     "dep:rustls",
     "ureq?/tls",
-    "cargo-xwin?/rustls-tls",
     "dep:rustls-pemfile",
 ]
 scaffolding = [
@@ -369,5 +355,3 @@ upload = [
     "wild",
     "dep:dirs",
 ]
-xwin = ["cargo-xwin"]
-zig = ["cargo-zigbuild"]
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<div class='path'>path: <a href='/guix/log/?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>root</a>/<a href='/guix/log/tests?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>tests</a>/<a href='/guix/log/tests/build-emacs-utils.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310'>build-emacs-utils.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/build-emacs-utils.scm?id=2f7e80102defc6c4e469d1dc94441e7f054e5310&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-07-13 10:49:40 -0400'>2022-07-13</span></td><td><a href='/guix/commit/tests/build-emacs-utils.scm?id=dcf133587ac7d73ba306a314e1a496a7efb9960b'>tests: build-emacs-utils: Allow test to pass on Emacs 27 too.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/build-emacs-utils.scm
("emacs-batch-script: raise &amp;emacs-batch-error on failure"): More loosely
match expected error string, which differs between Emacs 27 and Emacs 28.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-06-17 23:39:32 +0200'>2022-06-17</span></td><td><a href='/guix/commit/tests/build-emacs-utils.scm?id=c3afbd05bf541b31b122e6093ff10eabf6a47926'>guix: emacs-utils: Add emacs-header-parse.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/emacs-utils.scm (emacs-header-parse): New procedure.

* tests/build-emacs-utils.scm ("emacs-header-parse: fetch version",
  "emacs-header-parse: fetch keywords", "emacs-header-parse: fetch
  nonexistent author"): New tests.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Fredrik Salomonsson</td></tr>
<tr><td><span title='2022-06-17 23:39:31 +0200'>2022-06-17</span></td><td><a href='/guix/commit/tests/build-emacs-utils.scm?id=f8275916fc6fcb3dd9bd8ef7dc4ddce2dca98c7d'>guix: emacs-utils: Add emacs-batch-script.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/emacs-utils.scm (emacs-batch-script): New procedure.

* tests/build-emacs-utils.scm: New file.

* Makefile.am (TESTS): Add `tests/build-emacs-utils.scm'.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Fredrik Salomonsson</td></tr>