BL51: '*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL'

I am designing an application to run on the Si Labs
C8051F046 MCU with uVision 3. Yesterday I created a new
project, but forgot to include one of the source modules.
This produced a line during the link in the Output Window:

  *** WARNING L1: UNRESOLVED EXTERNAL SYMBOL

I missed it, as this program generates many similar warnings:

  *** WARNING L16: UNCALLED SEGMENT, IGNORED FOR OVERLAY PROCESS

(in that tiny, little output window) which I must ignore.
Because L1 is only a warning; BL51 completed the build and
gave me a load module, which I attempted to debug. (It came
fairly close to working). I wasted an hour tracking the
cause back to this source.

I can't think of any scenario where I would want the build
to continue with missing source modules, yet I can find no
tool that would allow me to make L1 an error instead of a
warning. As best I can tell, this topic has never appeared
in the knowledge base or on this forum.

Does anybody have a differing opinion? A workaround?

Advance thanks for any insight.

============================================================
Gary Lynch            |     To send mail, change no$pam in
lynchg@no$pam.com     |     my domain name to stacoenergy