USE_IMAKE not honoring PKGSRC_COMPILER

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

Maybe not a real problem, but I have my default cc and gcc in my path 
error to stderr and exit 1.

This causes:

=> Checking for portability problems in extracted files
imake -DUseInstalled -I/home/reed/pkg/lib/X11/config
Abort trap (core dumped)
*** Error code 134


I haven't had chance to look further than this ...

  Jeremy C. Reed