RSC_TO_S.PRG can be installed in the Devpac 3 Tools menu and called
when the file in the top window has the same filename as the resource
file (e.g. if resource is TEST.RSC, top window should contain TEST.S)

Use the following settings for the Tools menu entry:

Command Line:   As shown
Directory:              Tool's
Save Files:             Yes
Path:           D:\DEVPAC3\TOOLS\RSC_TO_S.PRG (or wherever it is)
Command:                %?
Pause on Return:        No
Report all errors:      No
Run as TOS:             No
RUN as GEM:             Yes