fix openjdk build for powerpc port

Add missing JDK7u environment variables and JDK8 configure flag.
export ant_home

Since Ant is automatically fetched and added to PATH by the script
it's best to export ANT_HOME as well.
add ppc64 to fastdebug build

Include detection of PPC64 arch, set BUILD_PROFILE, and add
an EXTRA_FLAGS for additional (but exclusive) configure flags.