Add Rust build metadata files

We need the target specification, the .rmeta fils and the .so file. Also
since we need to use the same compiler version to build out of tree
modules we bundle the rust-toolchain file as well.

PKGBUILD

@@ -18,15 +18,18 @@ _srcname=archlinux-linux
 source=(
   "$_srcname::git+https://github.com/archlinux/linux?signed#tag=$_srctag"
   config         # the main kernel config file
+  rust-toolchain
 )
 validpgpkeys=(
   'ABAF11C65A2970B130ABE3C479BE3E4300411886'  # Linus Torvalds
   '647F28654894E3BD457199BE38DBBDC86092693E'  # Greg Kroah-Hartman
   'A2FF3A36AAA56654109064AB19802F8B0D70FC30'  # Jan Alexander Steffens (heftig)
   'C7E7849466FE2358343588377258734B41C31549'  # David Runge <[email protected]>
 )
+
 sha256sums=('SKIP'
-            '165ebef778236af6407bd50ce99add5e247295b65073257c95514a09cc82d74a')
+            '165ebef778236af6407bd50ce99add5e247295b65073257c95514a09cc82d74a'
+            'bc43ef34a131fd2f99047a8aca491f24fa0a36010dcb90166e73c49f58a1928d')
 
 export KBUILD_BUILD_HOST=archlinux
 export KBUILD_BUILD_USER=$pkgbase
@@ -150,6 +153,14 @@ _package-headers() {
   echo "Removing loose objects..."
   find "$builddir" -type f -name '*.o' -printf 'Removing %P\n' -delete
 
+  # Rust support
+  echo "Installing Rust files..."
+  install -Dt "$builddir/rust" -m644 rust/target.json
+  install -Dt "$builddir/rust" -m644 rust/*.rmeta
+  install -Dt "$builddir/rust" -m644 rust/*.so
+  install -Dt "$builddir" -m644 ../../rust-toolchain
+
+
   echo "Stripping build tools..."
   local file
   while read -rd '' file; do