Cache GitHub Action build folders

.github/workflows/Linux_x86.yml

@@ -22,6 +22,13 @@ jobs:
         sudo apt update -y &&
         sudo apt install -y cmake file g++-multilib git libfmt-dev:i386 libsdl2-dev:i386 libsdl2-ttf-dev:i386 libsodium-dev:i386 rpm wget
 
+    - name: Cache CMake build folder
+      uses: actions/cache@v2
+      with:
+        path: build
+        key: linux-x86-cmake-${{ github.sha }}
+        restore-keys: linux-x86-cmake-
+
     - name: Configure CMake
       shell: bash
       working-directory: ${{github.workspace}}

.github/workflows/Linux_x86_64_SDL1.yml

@@ -21,6 +21,13 @@ jobs:
         sudo apt update &&
         sudo apt install -y cmake file g++ git libfmt-dev libsdl-dev libsdl-ttf2.0-dev libsodium-dev rpm
 
+    - name: Cache CMake build folder
+      uses: actions/cache@v2
+      with:
+        path: build
+        key: linux-x86_64-sdl1-cmake-${{ github.sha }}
+        restore-keys: linux-x86_64-sdl1-cmake-
+
     - name: Configure CMake
       shell: bash
       working-directory: ${{github.workspace}}

.github/workflows/MacOSX.yml

@@ -27,6 +27,13 @@ jobs:
     - name: Create Build Environment
       run: brew bundle install
 
+    - name: Cache CMake build folder
+      uses: actions/cache@v2
+      with:
+        path: build
+        key: ${{ runner.os }}-cmake-${{ github.sha }}
+        restore-keys: ${{ runner.os }}-cmake-
+
     - name: Configure CMake
       # Use a bash shell so we can use the same syntax for environment variable
       # access regardless of the host operating system

.github/workflows/Windows_x64.yml

@@ -22,6 +22,13 @@ jobs:
         sudo apt install -y cmake gcc-mingw-w64-x86-64 g++-mingw-w64-x86-64 pkg-config-mingw-w64-x86-64 wget git sudo &&
         sudo Packaging/windows/mingw-prep64.sh
 
+    - name: Cache CMake build folder
+      uses: actions/cache@v2
+      with:
+        path: build
+        key: windows-x86_64-cmake-${{ github.sha }}
+        restore-keys: windows-x86_64-cmake-
+
     - name: Configure CMake
       shell: bash
       working-directory: ${{github.workspace}}

.github/workflows/Windows_x86.yml

@@ -22,6 +22,13 @@ jobs:
         sudo apt install -y cmake gcc-mingw-w64-i686 g++-mingw-w64-i686 pkg-config-mingw-w64-i686 wget git sudo &&
         sudo Packaging/windows/mingw-prep.sh
 
+    - name: Cache CMake build folder
+      uses: actions/cache@v2
+      with:
+        path: build
+        key: windows-x86-cmake-${{ github.sha }}
+        restore-keys: windows-x86-cmake-
+
     - name: Configure CMake
       shell: bash
       working-directory: ${{github.workspace}}