[Build] Convert build system to raw cmake and remove premake layer

src/xenia/CMakeLists.txt

@@ -0,0 +1,49 @@
+# src/xenia/CMakeLists.txt - Master file for all xenia modules.
+
+# xenia-core (this directory's own sources)
+add_library(xenia-core STATIC)
+file(GLOB _core_sources   "${CMAKE_CURRENT_SOURCE_DIR}/*.h"
+  "${CMAKE_CURRENT_SOURCE_DIR}/*.cc"
+)
+target_sources(xenia-core PRIVATE ${_core_sources})
+target_link_libraries(xenia-core PUBLIC fmt xenia-base)
+xe_target_defaults(xenia-core)
+
+# All subdirectories
+add_subdirectory(base)
+add_subdirectory(cpu)
+add_subdirectory(cpu/backend/x64)
+add_subdirectory(apu)
+add_subdirectory(apu/nop)
+add_subdirectory(gpu)
+add_subdirectory(gpu/null)
+add_subdirectory(gpu/vulkan)
+add_subdirectory(hid)
+add_subdirectory(hid/nop)
+add_subdirectory(hid/skylander)
+add_subdirectory(kernel)
+add_subdirectory(patcher)
+add_subdirectory(ui)
+add_subdirectory(ui/vulkan)
+add_subdirectory(vfs)
+add_subdirectory(debug/ui)
+add_subdirectory(app/discord)
+add_subdirectory(app)
+
+# SDL-based modules (not Android)
+add_subdirectory(apu/sdl)
+add_subdirectory(helper/sdl)
+add_subdirectory(hid/sdl)
+
+# Platform-conditional modules
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  add_subdirectory(apu/alsa)
+endif()
+
+if(WIN32)
+  add_subdirectory(apu/xaudio2)
+  add_subdirectory(gpu/d3d12)
+  add_subdirectory(hid/winkey)
+  add_subdirectory(hid/xinput)
+  add_subdirectory(ui/d3d12)
+endif()