[OpenJDK 2D-Dev] RFR: 8170681 : Remove fontconfig header files from JDK source tree

[Philip Race]

Bug: https://bugs.openjdk.java.net/browse/JDK-8170681
Webrev: http://cr.openjdk.java.net/~prr/8170681/

This fix removes the copy of fontconfig.h from the JDK sources.

The file was originally included in the JDK sources because the
build platforms of the day were too old to include it.

It will henceforth rely on finding it in the build environment for
Linux and Solaris.

The build has been tested on all platforms.

The updated generated-configure.sh is not shown here since its
diff is not useful (easy to read) but will be checked in as part of the fix.

-phil.