Remove dead code from earlier R versions

Author: thisisnic

r/src/arrow_cpp11.h

@@ -38,17 +38,6 @@
 #define ARROW_R_DCHECK(EXPR)
 #endif
 
-#if (R_VERSION < R_Version(3, 5, 0))
-#define LOGICAL_RO(x) ((const int*)LOGICAL(x))
-#define INTEGER_RO(x) ((const int*)INTEGER(x))
-#define REAL_RO(x) ((const double*)REAL(x))
-#define COMPLEX_RO(x) ((const Rcomplex*)COMPLEX(x))
-#define STRING_PTR_RO(x) ((const SEXP*)STRING_PTR(x))
-#define RAW_RO(x) ((const Rbyte*)RAW(x))
-#define DATAPTR_RO(x) ((const void*)STRING_PTR(x))
-#define DATAPTR(x) (void*)STRING_PTR(x)
-#endif
-
 // R_altrep_class_name and R_altrep_class_package don't exist before R 4.6
 #if R_VERSION < R_Version(4, 6, 0)
 inline SEXP R_altrep_class_name(SEXP x) {