ci: set macos deployment target in CI builds

Author: mhulden

.github/workflows/ci.yml

@@ -73,6 +73,13 @@ jobs:
       - name: Install dependencies (macOS)
         if: runner.os == 'macOS'
         run: command -v cmake >/dev/null 2>&1 || brew install cmake
+      - name: Configure macOS deployment target
+        if: runner.os == 'macOS'
+        run: |
+          echo "MACOSX_DEPLOYMENT_TARGET=11.0" >> "$GITHUB_ENV"
+          echo "CMAKE_OSX_DEPLOYMENT_TARGET=11.0" >> "$GITHUB_ENV"
+          echo "CFLAGS=-mmacosx-version-min=11.0" >> "$GITHUB_ENV"
+          echo "CXXFLAGS=-mmacosx-version-min=11.0" >> "$GITHUB_ENV"
       - name: Install dependencies (Linux)
         if: runner.os == 'Linux'
         run: |
@@ -138,6 +145,13 @@ jobs:
       - name: Install dependencies (macOS)
         if: runner.os == 'macOS'
         run: command -v cmake >/dev/null 2>&1 || brew install cmake
+      - name: Configure macOS deployment target
+        if: runner.os == 'macOS'
+        run: |
+          echo "MACOSX_DEPLOYMENT_TARGET=11.0" >> "$GITHUB_ENV"
+          echo "CMAKE_OSX_DEPLOYMENT_TARGET=11.0" >> "$GITHUB_ENV"
+          echo "CFLAGS=-mmacosx-version-min=11.0" >> "$GITHUB_ENV"
+          echo "CXXFLAGS=-mmacosx-version-min=11.0" >> "$GITHUB_ENV"
       - name: Install dependencies (Linux)
         if: runner.os == 'Linux'
         run: |