[PATCH RFC 0/5] fix build errors with gcc6

[Guido Trentalancia]

Hello.

The following set of five patches aims to fix the errors that currently
occur during compilation of openjdk8u with gcc6.

I suppose some of the patches are trivial and can be applied easily
while others (in particular 4/5) would probably require more revision.

After applying the patchset, I can now build OpenJDK8 Update and it
seems to be working fine.

The following build options have been used:

--enable-unlimited-crypto
--with-extra-cflags="-O3 -march=nehalem -mtune=nehalem -Wno-error
-fpermissive -fno-delete-null-pointer-checks -fno-lifetime-dse"
--with-extra-cxxflags="-O3 -march=nehalem -mtune=nehalem -Wno-error
-fpermissive -fno-delete-null-pointer-checks -fno-lifetime-dse"
--with-boot-jdk=/usr/lib64/jdk1.7.0_04

Thanks very much to Seán Coffey for pointing me to the right mailing
list and to David Holmes for the initial review of patch 4/5.

Regards,

Guido