Only build benchmark dependencies when necessary

.github/workflows/build.yaml

@@ -143,6 +143,8 @@ jobs:
         with:
           command: check
           args: --benches --all-features
+        env:
+          RUSTFLAGS: "--cfg bench"
 
   test:
     name: Test (${{ matrix.os.name }}, ${{ matrix.rust }})
@@ -273,6 +275,8 @@ jobs:
         with:
           command: fmt
           args: --all -- --check
+        env:
+          RUSTFLAGS: "--cfg bench"
 
   clippy:
     name: Clippy
@@ -298,6 +302,8 @@ jobs:
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           args: --all-features --benches --tests
+        env:
+          RUSTFLAGS: "--cfg bench"
 
   documentation:
     name: Documentation

Cargo.toml

@@ -47,15 +47,17 @@ time-macros = { version = "=0.2.3", path = "time-macros", optional = true }
 libc = "0.2.98"
 
 [dev-dependencies]
-criterion = "0.3.5"
-criterion-cycles-per-byte = "0.1.2"
 rand = { version = "0.8.4", default-features = false }
 serde = { version = "1.0.126", default-features = false }
 serde_test = "1.0.126"
 
 [target.'cfg(__ui_tests)'.dev-dependencies]
 trybuild = "=1.0.34"
 
+[target.'cfg(bench)'.dev-dependencies]
+criterion = "0.3.5"
+criterion-cycles-per-byte = "0.1.2"
+
 # Significant contributions to the benchmarks provided by Emil Lundberg.
 [[bench]]
 name = "benchmarks"