Is there any example of compiling with a library (.a) file on SoC?

I found the clue here: https://developer.arm.com/docs/100070/latest/image-structure-and-generation/specifying-user-libraries-when-linking

You can use the

--library=name

option to specify static libraries, libname

.a.

So - even though the actual filename is libpth.a - however the build tool only works if I say it is: pth

the tool adds the lib at the front and the .a at the end, and will not countenance the user supplying the full (and valid!) filename!?!?!

good grief.