RFR (S): 8011198: LP64 setting is not preserved on Solaris after 8006965

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/8011198/webrev/

Fixed incremental build makefiles generated by buildtree.make.
Consolidated unix build.sh.
Fixed launcher.script (hotspot) to use .dbxrc from HOME dir since 
8006965 removed it from build dir.

Tested with jprt.

Thanks,
Vladimir