Fix macOS DMG startup crash by bundling libSDL3 for sdl2-compat

Author: andriiryzhkov

.ci/Brewfile

@@ -55,6 +55,7 @@ brew 'portmidi'
 brew 'potrace'
 brew 'pugixml'
 brew 'sdl2'
+brew 'sdl3'
 brew 'shared-mime-info'
 brew 'curl'
 brew 'perl'

packaging/macosx/3_make_hb_darktable_package.sh

@@ -249,6 +249,15 @@ for dtSharedObj in $dtSharedObjDirs; do
     cp -LR "$homebrewHome"/lib/"$dtSharedObj"/* "$dtResourcesDir"/lib/"$dtSharedObj"/
 done
 
+# Homebrew's `sdl2` is sdl2-compat, which dlopen()s libSDL3 at runtime —
+# otool can't see that, so install_dependencies misses it; copy explicitly
+sdl3Source="$homebrewHome/opt/sdl3/lib/libSDL3.dylib"
+if [[ -f "$sdl3Source" ]]; then
+    cp -L "$sdl3Source" "$dtResourcesDir"/lib/libSDL3.dylib
+    install_name_tool -id "@executable_path/../Resources/lib/libSDL3.dylib" \
+        "$dtResourcesDir"/lib/libSDL3.dylib || true
+fi
+
 dtSharedObjDirs="libgphoto2 libgphoto2_port"
 for dtSharedObj in $dtSharedObjDirs; do
     mkdir "$dtResourcesDir"/lib/"$dtSharedObj"