gnu: Add c2rust.

* gnu/packages/c2rust.scm (c2rust): New variable.
* gnu/packages/patches/c2rust-ast-exporter-local-search.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add reference to it.

Change-Id: I9a80c6071a48ab5baed0a83e1c2463f83a6c6b9b

gnu/local.mk

@@ -1046,6 +1046,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/byobu-writable-status.patch		\
   %D%/packages/patches/bubblewrap-fix-locale-in-tests.patch	\
   %D%/packages/patches/busybox-add-missing-sha-NI-guard.patch	\
+  %D%/packages/patches/c2rust-ast-exporter-local-search.patch	\
   %D%/packages/patches/cadical-add-shared-library.patch		\
   %D%/packages/patches/calibre-no-updates-dialog.patch		\
   %D%/packages/patches/calibre-remove-test-sqlite.patch		\

gnu/packages/c2rust.scm

@@ -249,3 +249,51 @@
     (synopsis "C2Rust transpiler implementation")
     (description "This package provides C2Rust transpiler implementation.")
     (license license:bsd-3)))
+
+(define-public c2rust
+  (package
+    (name "c2rust")
+    (version "0.18.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (crate-uri "c2rust" version))
+       (file-name (string-append name "-" version ".tar.gz"))
+       (sha256
+        (base32 "1rg9cvvmh9zw89mz2bpyvqlwbfhzl5dw2hab9z6d5rasr8mir7nh"))))
+    (build-system cargo-build-system)
+    (native-inputs
+     `(("tinycbor-src" ,%tinycbor-source)
+       ("cmake" ,cmake)
+       ("clang" ,clang)))
+    (inputs (list llvm))
+    (arguments
+     `(#:cargo-inputs (("rust-anyhow" ,rust-anyhow-1)
+                       ("rust-c2rust-build-paths" ,rust-c2rust-build-paths-0.18)
+                       ("rust-c2rust-transpile" ,rust-c2rust-transpile-0.18)
+                       ("rust-clap" ,rust-clap-3)
+                       ("rust-env-logger" ,rust-env-logger-0.10)
+                       ("rust-git-testament" ,rust-git-testament-0.2)
+                       ("rust-is-executable" ,rust-is-executable-1)
+                       ("rust-log" ,rust-log-0.4)
+                       ("rust-regex" ,rust-regex-1)
+                       ("rust-shlex" ,rust-shlex-1)
+                       ("rust-time-macros" ,rust-time-macros-0.2))
+       #:phases
+       (modify-phases %standard-phases
+         (add-after 'unpack 'patch-deps
+           (lambda _
+             ;; This is incorrect in the release to begin with.
+             (substitute* "Cargo.toml"
+              (("=0.2.6") "=0.2.18"))))
+         (add-before 'build 'patch
+           (lambda* (#:key inputs #:allow-other-keys)
+             ;; The build process will slightly patch the sources.
+             (copy-recursively (assoc-ref inputs "tinycbor-src")
+                               "/tmp/tinycbor")
+             (setenv "CMAKE_TINYCBOR_SOURCE_DIR" "/tmp/tinycbor"))))))
+    (home-page "https://c2rust.com/")
+    (synopsis "C to Rust translation, refactoring, and cross-checking")
+    (description
+     "This package provides C to Rust translation, refactoring, and cross-checking.")
+    (license license:bsd-3)))

gnu/packages/patches/c2rust-ast-exporter-local-search.patch

@@ -0,0 +1,24 @@
+diff -ru orig/c2rust-ast-exporter-0.18.0/src/CMakeLists.txt c2rust-ast-exporter-0.18.0/src/CMakeLists.txt
+--- orig/c2rust-ast-exporter-0.18.0/src/CMakeLists.txt	2006-07-24 03:21:28.000000000 +0200
++++ c2rust-ast-exporter-0.18.0/src/CMakeLists.txt	2024-12-21 12:06:27.056455735 +0100
+@@ -24,8 +24,7 @@
+ ExternalProject_Add(tinycbor_build
+             PREFIX ${TINYCBOR_PREFIX}
+             INSTALL_DIR ${CMAKE_BINARY_DIR}
+-            GIT_REPOSITORY ${TINYCBOR_REPO}
+-            GIT_TAG ${TINYCBOR_TAG}
++            SOURCE_DIR ${TINYCBOR_SOURCE_DIR}
+             # the fd redirection here fails when the build run inside Cargo.
+             # patch from upstream:
+             # https://github.com/intel/tinycbor/commit/6176e0a28d7c5ef3a5e9cbd02521999c412de72c
+diff -ru orig/c2rust-ast-exporter-0.18.0/build.rs c2rust-ast-exporter-0.18.0/build.rs
+--- orig/c2rust-ast-exporter-0.18.0/build.rs	2024-12-21 19:37:50.004786236 +0100
++++ c2rust-ast-exporter-0.18.0/build.rs	2024-12-21 19:39:20.188478196 +0100
+@@ -127,6 +127,7 @@
+             // Build libclangAstExporter.a with cmake
+             let dst = Config::new("src")
+                 // Where to find LLVM/Clang CMake files
++                .define("TINYCBOR_SOURCE_DIR", &env!("CMAKE_TINYCBOR_SOURCE_DIR"))
+                 .define("LLVM_DIR", &format!("{}/cmake/llvm", llvm_lib_dir))
+                 .define("Clang_DIR", &format!("{}/cmake/clang", llvm_lib_dir))
+                 // What to build