Move builtins-test-intrinsics out of the workspace

This crate doesn't need to be a default member since it requires the
opposite settings from everything else. Exclude it from the workspace
and run it only when explicitly requested.

This also makes `cargo t --no-default-features` work without additional
qualifiers. `--no-default-features` still needs to be passed to ensure
`#![compiler_builtins]` does not get set.

Author: tgross35

Cargo.toml

@@ -1,11 +1,7 @@
 [workspace]
 resolver = "3"
 members = [
-    # Note that builtins-test-intrinsics cannot be a default member because it
-    # needs the `mangled-names` feature disabled, while `builtins-test` needs
-    # it enabled.
     "builtins-test",
-    "builtins-test-intrinsics",
     "compiler-builtins",
     "crates/libm-macros",
     "libm",
@@ -24,6 +20,13 @@ default-members = [
     "libm",
 ]
 
+exclude = [
+    # `builtins-test-intrinsics` needs the feature `compiler-builtins` enabled
+    # and `mangled-names` disabled, which is the opposite of what is needed for
+    # other tests, so it makes sense to keep it out of the workspace.
+    "builtins-test-intrinsics",
+]
+
 [profile.release]
 panic = "abort"
 

builtins-test/Cargo.toml

@@ -5,10 +5,6 @@ authors = ["Alex Crichton <[email protected]>"]
 edition = "2024"
 publish = false
 
-[lib]
-test = false
-doctest = false
-
 [dependencies]
 # For fuzzing tests we want a deterministic seedable RNG. We also eliminate potential
 # problems with system RNGs on the variety of platforms this crate is tested on.

ci/run.sh

@@ -122,7 +122,9 @@ done
 rm -f "${rlib_paths[@]}"
 
 build_intrinsics_test() {
-    cargo build --target "$target" -v --package builtins-test-intrinsics "$@"
+    cargo build \
+        --target "$target" --verbose \
+        --manifest-path builtins-test-intrinsics/Cargo.toml "$@"
 }
 
 # Verify that we haven't dropped any intrinsics/symbols
@@ -133,10 +135,8 @@ build_intrinsics_test --features c --release
 
 # Verify that there are no undefined symbols to `panic` within our
 # implementations
-CARGO_PROFILE_DEV_LTO=true \
-    cargo build --target "$target" --package builtins-test-intrinsics
-CARGO_PROFILE_RELEASE_LTO=true \
-    cargo build --target "$target" --package builtins-test-intrinsics --release
+CARGO_PROFILE_DEV_LTO=true build_intrinsics_test
+CARGO_PROFILE_RELEASE_LTO=true build_intrinsics_test --release
 
 # Ensure no references to any symbols from core
 update_rlib_paths

compiler-builtins/Cargo.toml

@@ -25,8 +25,9 @@ include = [
 links = 'compiler-rt'
 
 [lib]
-test = false
 bench = false
+doctest = false
+test = false
 
 [dependencies]
 # For more information on this dependency see