Re-add libretro core

src/CMakeLists.txt

@@ -1,10 +1,16 @@
+if(BUILD_LIBRETRO_CORE)
+  add_definitions("-DLIBRETRO=1")
+endif()
+
 add_subdirectory(common)
 add_subdirectory(core)
 add_subdirectory(scmversion)
 
-add_subdirectory(common-tests)
-if(WIN32)
-  add_subdirectory(updater)
+if(NOT BUILD_LIBRETRO_CORE)
+  add_subdirectory(common-tests)
+  if(WIN32)
+    add_subdirectory(updater)
+  endif()
 endif()
 
 add_subdirectory(frontend-common)
@@ -16,3 +22,8 @@ endif()
 if(BUILD_QT_FRONTEND)
   add_subdirectory(duckstation-qt)
 endif()
+
+if(BUILD_LIBRETRO_CORE)
+  add_subdirectory(duckstation-libretro)
+endif()
+

src/common/CMakeLists.txt

@@ -222,6 +222,9 @@ endif()
 if(APPLE)
   # Needed for Vulkan Swap Chain.
   target_link_libraries(common PRIVATE "objc")
+endif()
+
+if(APPLE AND NOT BUILD_LIBRETRO_CORE)
   target_sources(common PRIVATE
     gl/context_agl.mm
     gl/context_agl.h

src/common/vulkan/shader_compiler.cpp

@@ -124,7 +124,9 @@ bool InitializeGlslang()
     return false;
   }
 
+#ifndef LIBRETRO
   std::atexit([]() { glslang::FinalizeProcess(); });
+#endif
 
   glslang_initialized = true;
   return true;

src/common/window_info.h

@@ -13,6 +13,7 @@ struct WindowInfo
     MacOS,
     Android,
     Display,
+    Libretro,
   };
 
   enum class SurfaceFormat