Try setting up several platforms

WORKSPACE

@@ -53,7 +53,7 @@ register_coreutils_toolchains()
 
 load("@musl_toolchains//:repositories.bzl", "load_musl_toolchains")
 
-load_musl_toolchains()
+load_musl_toolchains(extra_target_compatible_with = ["@//tools/linkers:musl"])
 
 load("@musl_toolchains//:toolchains.bzl", "register_musl_toolchains")
 
@@ -204,13 +204,22 @@ rust_repository_set(
         "aarch64-unknown-linux-musl": [
             "@platforms//cpu:arm64",
             "@platforms//os:linux",
+            "@//tools/linkers:musl",
+        ],
+        "aarch64-unknown-linux-gnu": [
+            "@platforms//cpu:arm64",
+            "@platforms//os:linux",
+            "@//tools/linkers:unknown",
         ],
         "x86_64-unknown-linux-gnu": [
-            "@platforms//:incompatible",
+            "@platforms//cpu:x86_64",
+            "@platforms//os:linux",
+            "@//tools/linkers:unknown",
         ],
         "x86_64-unknown-linux-musl": [
             "@platforms//cpu:x86_64",
             "@platforms//os:linux",
+            "@//tools/linkers:musl",
         ],
     },
     versions = [RUST_VERSION],

py/tools/venv_bin/BUILD.bazel

@@ -14,6 +14,7 @@ rust_binary(
         "@crate_index//:clap",
         "@crate_index//:miette",
     ],
+    tags = ["manual"],
 )
 
 alias(

tools/linkers/BUILD.bazel

@@ -0,0 +1,29 @@
+constraint_setting(
+    name = "linker",
+    default_constraint_value = ":unknown",
+    visibility = ["//visibility:public"],
+)
+
+constraint_value(
+    name = "musl",
+    constraint_setting = ":linker",
+    visibility = ["//visibility:public"],
+)
+
+# Default linker for anyone not setting the linker to `musl`.
+# You shouldn't ever need to set this value manually.
+constraint_value(
+    name = "unknown",
+    constraint_setting = ":linker",
+    visibility = ["//visibility:public"],
+)
+
+platform(
+    name = "linux_x86_64_musl",
+    constraint_values = [
+        ":musl",
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+    visibility = ["//visibility:public"],
+)