Use olibc as an alternate C library

[jserv]

Currently, olibc takes Android build system, which assumes the in-place build environment. However, it is not exact use scenario of olibc. At least, we should provide a wrapper script for {gcc,clang}, called olibc-{gcc,clang}, can be used in place of {gcc,clang} to compile and link programs and libraries against olibc.