change call for R to use mkCharLen where it exists (R versions >=

2.7.0).  This is necessary because later versions of R (>= 2.8.0)
depreciate creation of strings through vectors because this does not
allow R to use character caches


git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12014 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Lib/r/rfragments.swg

@@ -162,9 +162,20 @@ SWIG_FromCharPtrAndSize(const char* carray, size_t size)
 {
   SEXP t, c;
   if (!carray) return R_NilValue;
+/* See R internals document 1.10.  
+   MkCharLen was introduced in 2.7.0.  Use that instead of hand
+   creating vector.
+
+   Starting in 2.8.0 creating strings via vectors was deprecated in
+   order to allow for use of CHARSXP caches. */
+
   Rf_protect(t = Rf_allocVector(STRSXP, 1));
+#if R_VERSION >=  R_Version(2,7,0)
+  c = Rf_mkCharLen(carray, size);
+#else
   c = Rf_allocVector(CHARSXP, size);
   strncpy((char *)CHAR(c), carray, size);
+#endif
   SET_STRING_ELT(t, 0, c);
   Rf_unprotect(1);
   return t;