CBuilder, link: On Android, always return absolute paths to libraries

CBuilder, link: On Android, always return absolute paths to libraries

Several modules on CPAN expect being able to pass the library
name returned by ->link to DynaLoader::dl_load_file and have it Just Work.
However, because ->link returns relative paths, those modules ran afoul
of Android's linker, which will only look in a handful of hardcoded
system directories for relative libraries, plus whatever LD_LIBRARY_PATH
pointed to at the start of execution.

This commit makes ->link on Android always return an absolute path,
which will be found by the linker.