diff --git a/.github/workflows/linux-check.yaml b/.github/workflows/linux-check.yaml
index fe92a62be6..7ab6fb96fd 100644
--- a/.github/workflows/linux-check.yaml
+++ b/.github/workflows/linux-check.yaml
@@ -19,7 +19,53 @@ on:
       - xcode/**
 
 jobs:
-  linux-debug:
+  linux-no-unity:
+    name: Linux no unity build
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    steps:
+      - name: Free disk space by removing .NET, Android and Haskell
+        shell: bash
+        run: |
+          sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc
+
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Parallel submodules checkout
+        shell: bash
+        run: git submodule update --init --recursive --jobs=$(($(nproc) * 2))
+
+      - name: Install build tools and dependencies
+        shell: bash
+        run: |
+          sudo apt update -y
+          sudo apt install -y \
+              ninja-build \
+              qtbase5-dev \
+              libqt5svg5-dev \
+              clang-tools-11
+
+      - name: Configure
+        shell: bash
+        run: ./configure.sh
+
+      - name: CMake
+        shell: bash
+        env:
+          CC: clang-12
+          CXX: clang++-12
+        # -g1 should slightly reduce build time.
+        run: |
+          cmake . -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS=-g1 -DUNITY_DISABLE=ON
+
+      - name: Compile
+        shell: bash
+        working-directory: build
+        run: ninja
+
+  linux-matrix:
     name: Linux builds and tests
     runs-on: ubuntu-latest
     strategy:
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ce79125a2d..7ecc9f4c5a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,8 +8,10 @@ set(CMAKE_C_STANDARD 11)
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_C_EXTENSIONS OFF)
 
-if (NOT (DEFINED ENV{UNITY_DISABLE}))
-  message("Using unity builds, export UNITY_DISABLE=1 to disable it.")
+option(UNITY_DISABLE "Disable unity build" OFF)
+
+if (NOT UNITY_DISABLE)
+  message("Using unity builds, pass -DUNITY_DISABLE=ON to disable it.")
   set(CMAKE_UNITY_BUILD ON)
   set(CMAKE_UNITY_BUILD_BATCH_SIZE 50)
 endif()