Fix build compatibility for macOS 10.14 and below (#1280)

macOS 10.15 introduced full `std::filesystem::path` support.
Before that our use of it would cause the build to fail.
This was not caught because "-mmacosx-version-min=10.9" was only
being passed to clang++ for release builds.

This passes that flag in a new static CI test build, and introduces
a hack developed by @LIJI32 to silence the availability errors,
since we use features already available in macOS 10.9.

This means we are testing both "vanilla" building,
and building static binaries using the same configuration
as during release, which should help avoiding last-minute
surprises.

.github/workflows/testing.yml

@@ -4,14 +4,14 @@ on:
   - pull_request
 
 jobs:
-  unix-testing:
+  unix:
     strategy:
       matrix:
         os: [ubuntu-20.04, ubuntu-22.04, macos-11, macos-12]
         cxx: [g++, clang++]
         buildsys: [make, cmake]
         exclude:
-          # `gcc` is just an alias to `clang` on macOS, don't bother
+          # Don't use `g++` on macOS; it's just an alias to `clang++`.
           - os: macos-11
             cxx: g++
           - os: macos-12
@@ -24,9 +24,9 @@ jobs:
         shell: bash
         run: |
           ./.github/scripts/install_deps.sh ${{ matrix.os }}
-      # The `export` lines are to allow working on macOS...
-      # Apple's base version is severely outdated, not even supporting -Wall,
-      # but it overrides Homebrew's version nonetheless...
+      # Export `bison` to allow using the version we install from Homebrew,
+      # instead of the outdated one preinstalled on macOS (which doesn't
+      # even support `-Wall`...).
       - name: Build & install using Make
         if: matrix.buildsys == 'make'
         run: |
@@ -79,7 +79,64 @@ jobs:
         run: |
           test/run-tests.sh
 
-  windows-testing:
+  macos-static:
+    strategy:
+      matrix:
+        # Don't run on macOS 11; our setup makes clang segfault (YES).
+        os: [macos-12]
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install deps
+        shell: bash
+        run: |
+          ./.github/scripts/install_deps.sh ${{ matrix.os }}
+      # Export `bison` to allow using the version we install from Homebrew,
+      # instead of the outdated one preinstalled on macOS (which doesn't
+      # even support `-Wall`...).
+      - name: Build & install
+        run: |
+          export PATH="/usr/local/opt/bison/bin:$PATH"
+          make -j CXXFLAGS="-O3 -flto -DNDEBUG -mmacosx-version-min=10.9 -I include/hacks" PKG_CONFIG="pkg-config --static" PNGLDLIBS="$(pkg-config --static --libs-only-L libpng | cut -c 3-)/libpng.a $(pkg-config --static --libs-only-l libpng | sed s/-lpng[0-9]*//g)" Q=
+      - name: Package binaries
+        run: |
+          mkdir bins
+          cp rgb{asm,link,fix,gfx} bins
+      - name: Upload binaries
+        uses: actions/upload-artifact@v3
+        with:
+          name: rgbds-canary-${{ matrix.os }}-${{ matrix.buildsys }}
+          path: bins
+      - name: Compute test dependency cache params
+        id: test-deps-cache-params
+        shell: bash
+        run: |
+          paths=$(test/fetch-test-deps.sh --get-paths)
+          hash=$(test/fetch-test-deps.sh --get-hash)
+          tee -a <<<"paths=\"${paths//,/\\n}\"" $GITHUB_OUTPUT
+          tee -a <<<"hash=${hash%-}" $GITHUB_OUTPUT
+      - name: Check test dependency repositories cache
+        id: test-deps-cache
+        uses: actions/cache@v3
+        with:
+          path: ${{ fromJSON(steps.test-deps-cache-params.outputs.paths) }}
+          key: ${{ matrix.os }}-${{ steps.test-deps-cache-params.outputs.hash }}
+      - if: steps.test-deps-cache.outputs.cache-hit != 'true'
+        name: Fetch test dependency repositories
+        continue-on-error: true
+        run: |
+          test/fetch-test-deps.sh
+      - name: Install test dependency dependencies
+        shell: bash
+        run: |
+          test/fetch-test-deps.sh --get-deps ${{ matrix.os }}
+      - name: Run tests
+        shell: bash
+        run: |
+          test/run-tests.sh
+
+  windows:
     strategy:
       matrix:
         bits: [32, 64]
@@ -169,7 +226,7 @@ jobs:
           cp bins/*.dll test/gfx
           test/run-tests.sh
 
-  windows-xbuild:
+  windows-mingw-build:
     strategy:
       matrix:
         bits: [32, 64]
@@ -220,8 +277,8 @@ jobs:
             test/gfx/randtilegen.exe
             test/gfx/rgbgfx_test.exe
 
-  windows-xtesting:
-    needs: windows-xbuild
+  windows-mingw-testing:
+    needs: windows-mingw-build
     strategy:
       matrix:
         os: [windows-2019, windows-2022]