hg: build-infra/jdk9: Fix bug in Windows precompiled headers: Include file cannot contain absolute path (which is cygwin style).

[magnus.ihse.bursie at oracle.com]

Changeset: bfc541d74282
Author:    ihse
Date:      2015-11-10 22:41 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/rev/bfc541d74282

Fix bug in Windows precompiled headers: Include file cannot contain absolute path (which is cygwin style).

! make/common/NativeCompilation.gmk