Cl6x compile dynamic library to acess the global variable

Dear sir, now I compile the dynamic lib (dll) for keystone C6678 device, I want to use global variable in the dll program, the dll program is written as such:

int global_variable;

int test_func(void)

{

   global_variable = 0xFF;

}

I want to know how to compile the dll in CCS.

 Thank you.