gnu: Remove rust-libsqlite3-sys-0.18.

* gnu/packages/crates-io.scm (rust-libsqlite3-sys-0.18): Delete variable.

gnu/packages/crates-io.scm

@@ -30570,42 +30570,6 @@ single-cell and single-nucleus sequencing data.")
         ("rust-pkg-config" ,rust-pkg-config-0.3)
         ("rust-vcpkg" ,rust-vcpkg-0.2))))))
 
-(define-public rust-libsqlite3-sys-0.18
-  (package
-    (inherit rust-libsqlite3-sys-0.20)
-    (name "rust-libsqlite3-sys")
-    (version "0.18.0")
-    (source
-     (origin
-       (method url-fetch)
-       (uri (crate-uri "libsqlite3-sys" version))
-       (file-name
-        (string-append name "-" version ".tar.gz"))
-       (sha256
-        (base32
-         "1ggpbnis0rci97ln628y2v6pkgfhb6zgc8rsp444mkdfph14lw0y"))
-       (modules '((guix build utils)))
-       (snippet
-        '(begin
-           (delete-file-recursively "sqlite3")
-           ;; Enable unstable features
-           (substitute* "src/lib.rs"
-             (("#!\\[allow\\(non_snake_case, non_camel_case_types\\)\\]" all)
-              (string-append "#![feature(non_exhaustive)]\n" all)))))))
-    (arguments
-     `(#:cargo-inputs
-       ;; build-dependencies
-       (("rust-bindgen" ,rust-bindgen-0.53)
-        ("rust-cc" ,rust-cc-1)
-        ("rust-pkg-config" ,rust-pkg-config-0.3)
-        ("rust-vcpkg" ,rust-vcpkg-0.2))
-       #:phases
-       (modify-phases %standard-phases
-         (add-after 'unpack 'enable-unstable-features
-           (lambda _
-             (setenv "RUSTC_BOOTSTRAP" "1")
-             #t)))))))
-
 (define-public rust-libxml-0.3
   (package
     (name "rust-libxml")