Switch MinGW building to CMake

Automatically grabs and compiles libpng, and avoids having hacky lines in our Makefile
(the compiler specification *should* be orthogonal to the build target!)

Also move the MinGW package install to the `install_deps.sh` script,
to move logic off of the YAML.

.github/scripts/install_deps.sh

@@ -2,10 +2,32 @@
 # This script requires `sh` instead of `bash` because the latter is not always installed on FreeBSD.
 set -eu
 
-case "${1%%-*}" in
+case $# in
+	1) OS="$1"; TOOLSET=    ;;
+	2) OS="$1"; TOOLSET="$2";;
+	*) echo >&2 "Usage: $0 <os> [toolset]" && exit 1;;
+esac
+
+case "${OS%%-*}" in
 	ubuntu|debian)
-		sudo apt-get -qq update
-		sudo apt-get install -yq bison libpng-dev pkgconf
+		pkgs=bison
+		case "$TOOLSET" in
+			mingw32)
+				pkgs="$pkgs libz-mingw-w64-dev g++-mingw-w64-i686-win32"
+				TOOLSET=
+			;;
+			mingw64)
+				pkgs="$pkgs libz-mingw-w64-dev g++-mingw-w64-x86-64-win32"
+				TOOLSET=
+			;;
+			'' | lcov)
+				pkgs="$pkgs libpng-dev pkgconf $TOOLSET"
+				TOOLSET=
+			;;
+		esac
+		sudo apt-get update -qq
+		# shellcheck disable=SC2086 # (This word splitting is intentional.)
+		sudo apt-get install -yq $pkgs
 		;;
 	macos)
 		# macOS bundles GNU Make 3.81, which doesn't support synced output.
@@ -32,6 +54,11 @@ case "${1%%-*}" in
 		;;
 esac
 
+if [ -n "$TOOLSET" ]; then
+	printf >&2 'Unknown toolset `%s` for OS `%s`\n' "$TOOLSET" "$OS"
+	exit 1
+fi
+
 # Print some system info, for easier debugging.
 # https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-commands#grouping-log-lines
 

.github/scripts/mingw-w64-libpng-dev.sh

@@ -1,29 +0,0 @@
-#!/bin/bash
-set -euo pipefail
-
-pngver=1.6.56
-arch="$1"
-
-## Grab sources and check them
-
-wget http://downloads.sourceforge.net/project/libpng/libpng16/$pngver/libpng-$pngver.tar.xz
-echo f7d8bf1601b7804f583a254ab343a6549ca6cf27d255c302c47af2d9d36a6f18 \*libpng-$pngver.tar.xz | \
-	sha256sum -c -
-
-## Extract sources and patch them
-
-tar -xf libpng-$pngver.tar.xz
-
-## Start building!
-
-mkdir -p build
-cd build
-../libpng-$pngver/configure \
-	--host="$arch" --target="$arch" \
-	--prefix="/usr/$arch" \
-	--enable-shared --disable-static \
-	CPPFLAGS="-D_FORTIFY_SOURCE=2" \
-	CFLAGS="-O2 -pipe -fno-plt -fno-exceptions --param=ssp-buffer-size=4" \
-	LDFLAGS="-Wl,-O1,--sort-common,--as-needed -fstack-protector"
-make -kj
-sudo make install

.github/workflows/coverage.yml

@@ -11,16 +11,13 @@ env:
 
 jobs:
   coverage:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout repo
         uses: actions/checkout@v6
       - name: Install deps
         run: |
-          ./.github/scripts/install_deps.sh ubuntu
-      - name: Install LCOV
-        run: |
-          sudo apt-get install lcov
+          .github/scripts/install_deps.sh ubuntu-latest lcov
       - name: Install test dependency dependencies
         run: |
           test/fetch-test-deps.sh --get-deps ubuntu

.github/workflows/testing.yml

@@ -49,7 +49,7 @@ jobs:
         uses: actions/checkout@v6
       - name: Install deps
         run: |
-          ./.github/scripts/install_deps.sh ${{ matrix.os }}
+          .github/scripts/install_deps.sh ${{ matrix.os }}
       - name: Build & install using Make
         if: matrix.buildsys == 'make'
         run: |
@@ -113,7 +113,7 @@ jobs:
         uses: actions/checkout@v6
       - name: Install deps
         run: |
-          ./.github/scripts/install_deps.sh macos
+          .github/scripts/install_deps.sh macos
       - name: Cache library deps
         uses: actions/cache@v5
         with:
@@ -222,45 +222,29 @@ jobs:
     strategy:
       matrix:
         bits: [32, 64]
-        include:
-          - bits: 32
-            arch: i686
-            triplet: i686-w64-mingw32
-          - bits: 64
-            arch: x86-64
-            triplet: x86_64-w64-mingw32
       fail-fast: false
-    runs-on: ubuntu-22.04
-    env:
-      DIST_DIR: win${{ matrix.bits }}
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout repo
         uses: actions/checkout@v6
       - name: Install deps
         run: |
-          ./.github/scripts/install_deps.sh ubuntu
-      - name: Install MinGW
-        run: | # dpkg-dev is apparently required for pkg-config for cross-building
-          sudo apt-get install g++-mingw-w64-${{ matrix.arch }}-win32 mingw-w64-tools libz-mingw-w64-dev dpkg-dev
-      - name: Install libpng dev headers for MinGW
-        run: |
-          ./.github/scripts/mingw-w64-libpng-dev.sh ${{ matrix.triplet }}
+          .github/scripts/install_deps.sh ubuntu mingw${{ matrix.bits }}
       - name: Cross-build Windows binaries
-        run: |
-          make mingw${{ matrix.bits }} -kj Q=
+        run: | # MinGW does not support `--preset develop` sanitizers ASan or UBSan.
+          dll_search_dir=$(printf '%s\n' /usr/lib/gcc/*-w64-mingw32/*-win32 | tee -a /dev/stderr)
+          cmake -B build --preset develop -DSANITIZERS=OFF --toolchain cmake/toolchain-mingw${{ matrix.bits }}.cmake \
+            -DFETCHCONTENT_BASE_DIR="${{ env.DEPS_ROOT_DIR }}" -DDLL_SEARCH_DIRS="$dll_search_dir"
+          cmake --build build
       - name: Package binaries
-        run: | # DLL dependencies can be figured out using e.g. Dependency Walker or objdump -p
-          mkdir bins
-          mv -v rgb{asm,link,fix,gfx}.exe bins/
-          cp -v /usr/${{ matrix.triplet }}/lib/zlib1.dll bins
-          cp -v /usr/${{ matrix.triplet }}/bin/libpng16-16.dll bins
-          cp -v /usr/lib/gcc/${{ matrix.triplet }}/10-win32/lib{ssp-0,stdc++-6}.dll bins
-          [ "${{ matrix.bits }}" -ne 32 ] || cp -v /usr/lib/gcc/${{ matrix.triplet }}/10-win32/libgcc_s_dw2-1.dll bins
+        run: |
+          cmake --install build --prefix . --verbose --component binaries
+          cmake --install build --prefix . --verbose --component shared-libs
       - name: Upload Windows binaries
         uses: actions/upload-artifact@v7
         with:
           name: rgbds-canary-mingw-win${{ matrix.bits }}
-          path: bins
+          path: bin
           if-no-files-found: error
       - name: Upload Windows test binaries
         uses: actions/upload-artifact@v7