[rubygems/rubygems] Removed ccache or sccache from args of Rust builder

```
 "  = note: some arguments are omitted. use `--verbose` to show all linker arguments\n" +
 "  = note: error: unexpected argument '-W' found\n" +
 "          \n" +
 "            tip: to pass '-W' as a value, use '-- -W'\n" +
 "          \n" +
 "          Usage: sccache [OPTIONS] <--dist-auth|--debug-preprocessor-cache|--dist-status|--show-stats|--show-adv-stats|--start-server|--stop-server|--zero-stats|--package-toolchain <EXE> <OUT>|CMD>\n" +
 "          \n" +
 "          For more information, try '--help'.\n" +
 "          \n" +
```

ruby/rubygems@45e688ae62

Author: hsbt

lib/rubygems/ext/cargo_builder.rb

@@ -158,6 +158,10 @@ def platform_specific_rustc_args(dest_dir, flags = [])
   # mkmf work properly.
   def linker_args
     cc_flag = self.class.shellsplit(makefile_config("CC"))
+    # Avoid to ccache like tool from Rust build
+    # see https://github.com/rubygems/rubygems/pull/8521#issuecomment-2689854359
+    # ex. CC="ccache gcc" or CC="sccache clang --any --args"
+    cc_flag.shift if cc_flag.size >= 2 && !cc_flag[1].start_with?("-")
     linker = cc_flag.shift
     link_args = cc_flag.flat_map {|a| ["-C", "link-arg=#{a}"] }
 

test/rubygems/test_gem_ext_cargo_builder.rb

@@ -141,6 +141,58 @@ def test_custom_name
     end
   end
 
+  def test_linker_args
+    orig_cc = RbConfig::MAKEFILE_CONFIG["CC"]
+    RbConfig::MAKEFILE_CONFIG["CC"] = "clang"
+
+    builder = Gem::Ext::CargoBuilder.new
+    args = builder.send(:linker_args)
+
+    assert args[1], "linker=clang"
+    assert_nil args[2]
+  ensure
+    RbConfig::MAKEFILE_CONFIG["CC"] = orig_cc
+  end
+
+  def test_linker_args_with_options
+    orig_cc = RbConfig::MAKEFILE_CONFIG["CC"]
+    RbConfig::MAKEFILE_CONFIG["CC"] = "gcc -Wl,--no-undefined"
+
+    builder = Gem::Ext::CargoBuilder.new
+    args = builder.send(:linker_args)
+
+    assert args[1], "linker=clang"
+    assert args[3], "link-args=-Wl,--no-undefined"
+  ensure
+    RbConfig::MAKEFILE_CONFIG["CC"] = orig_cc
+  end
+
+  def test_linker_args_with_cachetools
+    orig_cc = RbConfig::MAKEFILE_CONFIG["CC"]
+    RbConfig::MAKEFILE_CONFIG["CC"] = "sccache clang"
+
+    builder = Gem::Ext::CargoBuilder.new
+    args = builder.send(:linker_args)
+
+    assert args[1], "linker=clang"
+    assert_nil args[2]
+  ensure
+    RbConfig::MAKEFILE_CONFIG["CC"] = orig_cc
+  end
+
+  def test_linker_args_with_cachetools_and_options
+    orig_cc = RbConfig::MAKEFILE_CONFIG["CC"]
+    RbConfig::MAKEFILE_CONFIG["CC"] = "ccache gcc -Wl,--no-undefined"
+
+    builder = Gem::Ext::CargoBuilder.new
+    args = builder.send(:linker_args)
+
+    assert args[1], "linker=clang"
+    assert args[3], "link-args=-Wl,--no-undefined"
+  ensure
+    RbConfig::MAKEFILE_CONFIG["CC"] = orig_cc
+  end
+
   private
 
   def skip_unsupported_platforms!