Review Request: 8003945: build-infra: problems finding compiler when using --with-dev-kit

[Erik Joelsson]

This fix changes how configure looks for the compiler when 
--with-dev-kit or --with-sysroot is used. Instead of looking for each 
possible compiler name in all locations, it first looks for all compiler 
names in the dev-kit directory and only if that fails, falls back to the 
PATH variable.

http://cr.openjdk.java.net/~erikj/8003945/webrev.root.01/

/Erik