r.in.pbm.c is a replacement file for:
../../src.contrib/SCS/raster/r.ppm/cmd/r.in.ppm.c

which has the same functionality, 
but this one also allows the use of
portable BITmaps which are non-ascii.

BUT: Limitation to 32768 colors. 
     Use (new 5.0) r.in.ppm instead.
