Improve Rust build infrastructure

Further usage of this (coming in future changes) revealed some issues.

Change-Id: Ib60968c580db4e7bb4bd60c782ce7f93a7fc594d
Signed-off-by: Brian Silverman <bsilver16384@gmail.com>
diff --git a/build_tests/BUILD b/build_tests/BUILD
index 24fdad8..dc76f45 100644
--- a/build_tests/BUILD
+++ b/build_tests/BUILD
@@ -141,19 +141,19 @@
 rust_library(
     name = "hello_lib",
     srcs = ["hello_lib.rs"],
-    target_compatible_with = ["@platforms//os:linux"],
+    target_compatible_with = ["//tools/platforms/rust:has_support"],
 )
 
 rust_test(
     name = "hello_lib_test",
     crate = ":hello_lib",
-    target_compatible_with = ["@platforms//os:linux"],
+    target_compatible_with = ["//tools/platforms/rust:has_support"],
 )
 
 rust_binary(
     name = "rust_hello",
     srcs = ["rust_hello.rs"],
-    target_compatible_with = ["@platforms//os:linux"],
+    target_compatible_with = ["//tools/platforms/rust:has_support"],
     deps = [":hello_lib"],
 )
 
@@ -182,7 +182,7 @@
 rust_library(
     name = "rust_in_cc_rs",
     srcs = ["rust_in_cc.rs"],
-    target_compatible_with = ["@platforms//os:linux"],
+    target_compatible_with = ["//tools/platforms/rust:has_support"],
 )
 
 cc_test(