Enables Vcpkg usage for CMake builds

Configures CMake to utilize vcpkg for dependency management on both Linux and Windows platforms.
This ensures consistent build environments across different operating systems and simplifies the integration of external libraries.

.github/workflows/cmake-multi-platform.yml

@@ -21,8 +21,6 @@ jobs:
     container: archlinux:latest
     env:
       VCPKG_ROOT: ${{ github.workspace }}/vcpkg
-      OMATH_BUILD_VIA_VCPKG: ON
-
     steps:
       - name: Install basic tool-chain with pacman
         shell: bash
@@ -42,7 +40,7 @@ jobs:
           git clone --depth 1 https://github.com/microsoft/vcpkg "$VCPKG_ROOT"
       - name: Configure (cmake --preset)
         shell: bash
-        run: cmake --preset linux-release -DOMATH_BUILD_TESTS=ON -DOMATH_BUILD_BENCHMARK=OFF
+        run: cmake --preset linux-release -DOMATH_BUILD_TESTS=ON -DOMATH_BUILD_BENCHMARK=OFF -DOMATH_BUILD_VIA_VCPKG=ON
 
       - name: Build
         shell: bash
@@ -61,7 +59,6 @@ jobs:
     name: Windows (MSVC)
     runs-on: windows-latest
     env:
-      VCPKG_ROOT: ${{ github.workspace }}\vcpkg
       OMATH_BUILD_VIA_VCPKG: ON
 
     steps:
@@ -76,14 +73,9 @@ jobs:
       - name: Set up MSVC developer command-prompt
         uses: ilammy/msvc-dev-cmd@v1
 
-      - name: Set up vcpkg
-        shell: pwsh
-        run: |
-          git clone --depth 1 https://github.com/microsoft/vcpkg $env:VCPKG_ROOT
-
       - name: Configure (cmake --preset)
         shell: bash
-        run: cmake --preset windows-release -DOMATH_BUILD_TESTS=ON -DOMATH_BUILD_BENCHMARK=OFF
+        run: cmake --preset windows-release -DOMATH_BUILD_TESTS=ON -DOMATH_BUILD_BENCHMARK=OFF -DOMATH_BUILD_VIA_VCPKG=ON
 
       - name: Build
         shell: bash