FFI additions

com.oracle.truffle.r.native/fficall/jni/src/misc.c

com.oracle.truffle.r.native/fficall/jni/src/rf_functions.c

com.oracle.truffle.r.native/fficall/jni/src/rffiutils.c

com.oracle.truffle.r.native/fficall/jni/src/rffiutils.h

com.oracle.truffle.r.native/fficall/jni/src/variables.c

com.oracle.truffle.r.native/include/jni/ed_Rinterface

com.oracle.truffle.r.native/include/jni/ed_Rinternals

com.oracle.truffle.r.native/run/Makefile

.../com/oracle/truffle/r/runtime/ffi/jnr/CallRFFIHelper.java

...com/oracle/truffle/r/runtime/ffi/jnr/CallRFFIWithJNI.java