rffi: C, Call, Grid, Lapack, PCRE, RAppl, STats, Tools, UserRNG as Truffle Node; refactor ForeignFunctions to keep C/Fortran together

rffi: add interface for RFFI upcalls; refactor native layer to use instance not static class; add factory for alternate upcall implementations

refactor TestRFFIPackage, add more tests; (pessimally) fix “complete” status of vectors updated in RFFI

set XZ_HOME package download, fix -m64 regression in GNU R build for Solaris, solaris arch is sparcv9

Make definitions of some native functions available as expected by packages that expect USE_RINTERNALS to be set.