link makefile.in to Makefile.in for Android fdlibm build
a few tweaks to fix the OS X Android class library build

With corresponding changes to libcore, all the tests are passing
except Datagrams, which fails with a NPE in
NetworkInterface.getNetworkInterfacesList due to OS X not having
/sys/class/net.  Porting that class to OS X looks like a non-trivial
task.