Review Request: 8003317: build-infra: Configure fails when current dir is part of a symlink

[Erik Joelsson]

This is a fix for the logic that prevents configure from creating 
configurations in undesired directories. If the path to the source root 
contains a symlink, the check got fooled and refused to create a 
configuration anywhere. This is currently happening in REs nightly 
builds of build-infra for solaris-sparc.

http://cr.openjdk.java.net/~erikj/8003317/webrev.root.01/
As usual, please remember to regenerate configure after applying the 
patch and to also commit in jdk/make/closed when pushing.

/Erik