User selectable baud rate

[richard]

as you have discovered something can only be defined once
a workable option is to
DEFINE HSER_BAUD 19200 ; your default baud rate
then at boot up read your dip sw
if its necessary to alter baud rate then
the SPBRG register can be altered to suit the new baud rate.
you have provided no code or pic type or osc freq so you will need to calculate the spbrg value yourself
or find PicMulticalc by misterE