RFR (XS) 8250605: Linux x86_32 builds fail after JDK-8249821

[Aleksey Shipilev]

Bug:
  https://bugs.openjdk.java.net/browse/JDK-8250605

I believe this happens because int-to-pointer-cast is now enabled for libfontmanager. Below is the
minimal fix, but I wonder if we should reinstate the disabled warning for clang (in the same manner)
and msvc (which warning code that one is?). Or we can wait for follow-up bug reports there...

Minimal fix:
  https://cr.openjdk.java.net/~shade/8250605/webrev.01/

Testing: Linux {x86_64, x86_32} builds; jdk-submit (running)

-- 
Thanks,
-Aleksey