Has anyone had any luck adding usb device networking to a project outside of samples/net/echo_server ?
I have built the above project with -DCONF_FILE="prj.conf overlay-netusb.conf" and it appears to work correctly.
But, when I add the overlay-netusb.conf file to another project - in particular, samples/net/sntp_client, the file nrfx_usbd.c
fails to compile.

The compile problem shows up when compiling nrfx_usbd.c (which compiles fine in the echo_server project).  There are
a number of complaints; but I suspect they have the same root cause - undiscovered as yet!

In file included from /home/mcp/ZephyrProjects/zephyr-1_13_99/zephyr/ext/hal/nordic/nrfx/nrfx.h:37:0,
                 from /home/mcp/ZephyrProjects/zephyr-1_13_99/zephyr/ext/hal/nordic/nrfx/drivers/src/nrfx_usbd.c:32:
/home/mcp/ZephyrProjects/zephyr-1_13_99/zephyr/ext/hal/nordic/nrfx/drivers/src/nrfx_usbd.c:161:5: error: expected declaration specifiers or ‘...’ before ‘(’ token
     ((NRF_USBD_EPIN_CHECK(ep) ? NRFX_USBD_EPIN_BITPOS_0 : NRFX_USBD_EPOUT_BITPOS_0) \
     ^
/home/mcp/ZephyrProjects/zephyr-1_13_99/zephyr/ext/hal/nordic/./nrfx_glue.h:65:23: note: in definition of macro ‘NRFX_STATIC_ASSERT’
         static_assert(expression, "assertion failed")
                       ^~~~~~~~~~
/home/mcp/ZephyrProjects/zephyr-1_13_99/zephyr/ext/hal/nordic/nrfx/drivers/src/nrfx_usbd.c:185:20: note: in expansion of macro ‘NRFX_USBD_EP_BITPOS’
 NRFX_STATIC_ASSERT(NRFX_USBD_EP_BITPOS(NRFX_USBD_EPIN1)  == USBD_EPDATASTATUS_EPIN1_Pos );
                    ^~~~~~~~~~~~~~~~~~~

From what I can see, macro processor can't find a symbol it needs for evaluation.  I think most of the include files are actually static and not created by cmake.
So, I don't expect any problems there. The .config files generated for both projects are the same viz. networking and the generated dts .h files for both projects are identical.

Has anyone integrated USB device networking into a non sample project.

Thanks,
Chuck McP