I believe that what you're asking for is impossible and I have 2 pieces of evidence for this:
awk(1) man page doesn't have a
FILES section that lists any files related to the operation of
awk. Contrast that, for example, with the
bash(1) man page that lists all of Bash's initialization files in a separate
FILES section. Most commands whose behavior can be modified by configuration files, will name these files in their man page(s).
ENVIRONMENT VARIABLES section in the
awk(1) man page also doesn't mention any environment variables related to the loading of external files except for
GAWK_PATH in the case of
gawk, which tells it where to look for files named with the
I know this evidence isn't exactly conclusive, but barring any counterexamples, I'd say there's a very high chance you won't be able to accomplish this without using
-f and/or aliasing
awk as terdon suggested.