Adds back cmake error on x86-64 hosts

CMakeLists.txt

@@ -118,6 +118,12 @@ else()
 endif()
 
 if (CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64")
+  option(ENABLE_X86_HOST_DEBUG "Enables compiling on x86_64 host" FALSE)
+  if (NOT ENABLE_X86_HOST_DEBUG)
+    message(FATAL_ERROR
+    " FEX-Emu doesn't support compiling for x86-64 hosts!"
+    " This is /only/ a supported configuration for FEX CI and nothing else!")
+  endif()
   set(_M_X86_64 1)
   add_definitions(-D_M_X86_64=1)
   set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mcx16")