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

src/xenia/cpu/backend/x64/CMakeLists.txt

@@ -0,0 +1,18 @@
+add_library(xenia-cpu-backend-x64 STATIC)
+xe_platform_sources(xenia-cpu-backend-x64 ${CMAKE_CURRENT_SOURCE_DIR})
+target_compile_definitions(xenia-cpu-backend-x64 PRIVATE
+  CAPSTONE_X86_ATT_DISABLE
+  CAPSTONE_HAS_X86
+  CAPSTONE_USE_SYS_DYN_MEM
+  XBYAK_NO_OP_NAMES
+  XBYAK_ENABLE_OMITTED_OPERAND
+)
+# Optional VTune support
+if(EXISTS "${PROJECT_SOURCE_DIR}/third_party/vtune")
+  target_compile_definitions(xenia-cpu-backend-x64 PRIVATE ENABLE_VTUNE=1)
+endif()
+target_include_directories(xenia-cpu-backend-x64 PRIVATE
+  ${PROJECT_SOURCE_DIR}/third_party/capstone/include
+)
+target_link_libraries(xenia-cpu-backend-x64 PUBLIC capstone fmt xenia-base xenia-cpu)
+xe_target_defaults(xenia-cpu-backend-x64)