gnu: corrosion: Honor CARGO_BUILD_TARGET.

This change integrates Rust cross-compilation support from Guix.

* gnu/packages/patches/corrosion-honor-CARGO_BUILD_TARGET.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/cmake.scm (corrosion)[source]: Apply it.

Change-Id: I319f07f49e390ed84286f35aaa0bd3cad2ad70db

gnu/local.mk

@@ -1157,6 +1157,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/corefx-mono-5.4.0-patches.patch		\
   %D%/packages/patches/corefx-mono-pre-5.8.0-patches.patch	\
   %D%/packages/patches/coreutils-gnulib-tests.patch		\
+  %D%/packages/patches/corrosion-honor-CARGO_BUILD_TARGET.patch	\
   %D%/packages/patches/cppcheck-fix-basedir-test.patch	\
   %D%/packages/patches/cppdap-add-CPPDAP_USE_EXTERNAL_GTEST_PACKAGE.patch\
   %D%/packages/patches/cpulimit-with-glib-2.32.patch		\

gnu/packages/cmake.scm

@@ -508,7 +508,9 @@ format (either JSON or XML).
                     (commit (string-append "v" version))))
               (file-name (git-file-name name version))
               (sha256
-               (base32 "1bylfjji4yw88r00hgb69nfl9lz73bhc7q3n64myif4alr4b8ypx"))))
+               (base32 "1bylfjji4yw88r00hgb69nfl9lz73bhc7q3n64myif4alr4b8ypx"))
+              (patches
+               (search-patches "corrosion-honor-CARGO_BUILD_TARGET.patch"))))
     (build-system cmake-build-system)
     (arguments
      (list

gnu/packages/patches/corrosion-honor-CARGO_BUILD_TARGET.patch

@@ -0,0 +1,26 @@
+From 0a6f23a404d1b972b1c5f0cf1d38500276f3c9d1 Mon Sep 17 00:00:00 2001
+From: Hilton Chain <hako@ultrarare.space>
+Date: Tue, 22 Apr 2025 19:43:00 +0800
+Subject: [PATCH] Support Cargo target from environment variable.
+
+---
+ cmake/FindRust.cmake | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/cmake/FindRust.cmake b/cmake/FindRust.cmake
+index fccfac3..e888149 100644
+--- a/cmake/FindRust.cmake
++++ b/cmake/FindRust.cmake
+@@ -734,6 +734,9 @@ if (NOT Rust_CARGO_TARGET_CACHED)
+             set(Rust_CARGO_TARGET_CACHED "${_RUST_OHOS_TARGET}" CACHE STRING "Target triple")
+         endif()
+     endif()
++    if(DEFINED ENV{CARGO_BUILD_TARGET})
++        set(Rust_CARGO_TARGET_CACHED "$ENV{CARGO_BUILD_TARGET}")
++    endif()
+     # Fallback to the default host target
+     if(NOT Rust_CARGO_TARGET_CACHED)
+         if(CMAKE_CROSSCOMPILING)
+-- 
+2.49.0
+