Set CMAKE_<LANG>_BYTE_ORDER (#20455)

This helps libevent which depends on CMake setting CMAKE_C_BYTE_ORDER.

Author: eagleoflqj

cmake/Modules/Platform/Emscripten.cmake

@@ -303,6 +303,8 @@ set(CMAKE_HAVE_UNISTD_H 1)
 set(CMAKE_HAVE_PTHREAD_H 1)
 set(CMAKE_HAVE_SYS_PRCTL_H 1)
 set(CMAKE_WORDS_BIGENDIAN 0)
+set(CMAKE_C_BYTE_ORDER "LITTLE_ENDIAN")
+set(CMAKE_CXX_BYTE_ORDER "LITTLE_ENDIAN")
 set(CMAKE_DL_LIBS)
 
 function(em_validate_asmjs_after_build target)