Add --separate-64 to package-release.sh

NDK package may become too big with the inclusion of 64-bit
toolchain.  Add a new switch to optionally separate 64-bit
toolchain to its own package.

Also fix to remove sysroot from 64-bit windows toolchain

Change-Id: I5d54bfc351a8b5a6192d727984f7c8c555bd74d7
1 file changed