Support configuable prebuilt library path pattern

[chen3feng]

Now, the path pattern is hard-coded as lib64/lib.a, this design make it configuable:
cc_library(
prebuilt=True,
pattern = 'lib$bits/lib$name.$suffix'
)
here, $bits means bits, $name means name, $suffix means suffix. other vars are:
$arch
$os
$cc
$profile

[chen3feng]

done