symbol lookup changes

...src/com/oracle/truffle/r/engine/TruffleRLanguageImpl.java

.../com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_Base.java

.../com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_Call.java

...oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_NativeDLL.java

.../com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_PCRE.java

...m/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_PkgInit.java

...com/oracle/truffle/r/ffi/impl/llvm/TruffleLLVM_Tools.java

...om/oracle/truffle/r/nodes/builtin/fastr/FastRInterop.java

...me/src/com/oracle/truffle/r/runtime/context/RContext.java