* build script: improved arch handling: 1) actually build for the selected arch (size), 2) if x32 is selected, build for armv7 if arm, build for i*86 if i*86 (i386, i486, i586, i686) or build for i686 if x86_64/amd64, 3) if x64, build for arm64 if arm and build for x86_64 for everything else