lDebug wants to access the environment while executing
as a device driver. Instead of building it in a variable
then copying it to 68h:0 after FDCONFIG.SYS processing,
just build it there to begin with.
GCC has -mrtd but the args are pushed in reverse versus PASCAL. So asm
routines have to use macros to obtain the stack arguments.
For the complex call_nls assembly, revert the arguments in C using a
preprocessor macro.
