Reduce CI space requirements (#685)

Introduce `smol` profile for smaller, faster builds. The new profile
reduces the size of the `target` directory from ~12GB to ~1GB.

Fixes recent CI breakages due to "no space left on device" errors.

.bazelrc

@@ -53,7 +53,7 @@ test --output_groups=+clippy_checks
 build:nightly --@rules_rust//rust/toolchain/channel=nightly
 
 # AddressSanitizer to detect memory leaks.
-build:asan --config=nightly -c dbg
+build:asan --config=nightly
 build:asan --@rules_rust//:extra_rustc_flags=-Zsanitizer=address
 
 # ThreadSanitizer to detect data races. Tests under tsan shouldn't be cached

.github/workflows/native-cargo.yaml

@@ -31,7 +31,7 @@ jobs:
         shell: bash
 
       - name: Build on ${{ runner.os }}
-        run: cargo build --all
+        run: cargo build --all --profile=smol
 
       - name: Test on ${{ runner.os }}
-        run: cargo test --all
+        run: cargo test --all --profile=smol

.github/workflows/nix.yaml

@@ -81,4 +81,4 @@ jobs:
       - name: Invoke Cargo build in Nix shell
         run: >
           nix develop --impure --command
-          bash -c "cargo test --all"
+          bash -c "cargo test --all --profile=smol"

Cargo.toml

@@ -10,6 +10,14 @@ edition = "2021"
 lto = true
 opt-level = 3
 
+# Prefer this profile in CI, for instance via `cargo test --all --profile=smol`.
+# It reduces the size of the `target` directory from ~12GB to ~1GB.
+[profile.smol]
+inherits = "release"
+lto = "thin"
+opt-level = "z"
+strip = true
+
 [[bin]]
 name = "nativelink"