diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 5f46eb9..7aab5b5 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -50,9 +50,7 @@ jobs:
           else
             git clone https://github.com/rbenv/ruby-build.git
             PREFIX=/usr/local sudo ./ruby-build/install.sh
-            export MAKEFLAGS="-j$(nproc)"
-            export RUBY_CONFIGURE_OPTS="--disable-shared --disable-install-doc --disable-install-rdoc"
-            sudo ruby-build ${{ matrix.ruby_version }} /opt/rubies/${{ matrix.ruby_version }}
+            RUBY_CONFIGURE_OPTS="--disable-shared --disable-install-doc --disable-install-rdoc" sudo ruby-build ${{ matrix.ruby_version }} /opt/rubies/${{ matrix.ruby_version }}
           fi
       - name: Clippy
         run: cargo clippy --all-features --verbose -- -D warnings