preproc.c: make %warning actually issue a warning...
preproc.c: make %warning actually issue a warning...

The calculation of "severity" was buggered up, with the result that
%warning actually issued an error.

turingstudio/nasm,projedi/nasm,projedi/nasm,techkey/nasm,Distrotech/nasm,letolabs/nasm,turingstudio/nasm,techkey/nasm,Distrotech/nasm,projedi/nasm,turingstudio/nasm,techkey/nasm,letolabs/nasm,letolabs/nasm,projedi/nasm,techkey/nasm,Distrotech/nasm,turingstudio/nasm,projedi/nasm,techkey/nasm,Distrotech/nasm