Review Request: 8001941: build-infra: --disable-precompiled-headers does not seem to work

[Erik Joelsson]

This is a fix for configure parameter --disable-precompiled-headers. It 
has now been verified to work.

http://cr.openjdk.java.net/~erikj/8001941/webrev.root.01/ 
<http://cr.openjdk.java.net/%7Eerikj/8001941/webrev.root.01/>

Remember to regenerate configure after applying the patch and to also 
submit in jdk/make/closed.

/Erik