meson: remove unnecessary parts of cross file

Meson cross files layer, the last value of each key takes effect.

https: //mesonbuild.com/Machine-files.html#loading-multiple-machine-files
Change-Id: I22d886f71cd51f0ce520d3fc22aed4bcf074bb91

package.nix

@@ -116,21 +116,12 @@ let
     in
     builtins.toFile "lix-cross-file.conf" ''
       [properties]
-      bindgen_clang_arguments = ['-target', '${stdenv.targetPlatform.config}']
       # Meson is convinced that if !buildPlatform.canExecute hostPlatform then we cannot
       # build anything at all, which is not at all correct. If we can't execute the host
       # platform, we'll just disable tests and doc gen.
       needs_exe_wrapper = false
 
-      [host_machine]
-      system = '${stdenv.targetPlatform.parsed.kernel.name}'
-      cpu_family = '${cpuFamily stdenv.targetPlatform}'
-      cpu = '${stdenv.targetPlatform.parsed.cpu.name}'
-      endian = ${if stdenv.targetPlatform.isLittleEndian then "'little'" else "'big'"}
-
       [binaries]
-      llvm-config = 'llvm-config-native'
-      rust = ['rustc', '--target', '${stdenv.targetPlatform.rust.rustcTargetSpec}']
       # Meson refuses to consider any CMake binary during cross compilation if it's
       # not explicitly specified here, in the cross file.
       # https://github.com/mesonbuild/meson/blob/0ed78cf6fa6d87c0738f67ae43525e661b50a8a2/mesonbuild/cmake/executor.py#L72