restore ability to supply include information via -I to client packages

Author: eddelbuettel

ChangeLog

@@ -1,3 +1,8 @@
+2014-01-17  Dirk Eddelbuettel  <edd@debian.org>
+
+	* R/RcppLdpath.R (RcppCxxFlags): Restore function to supply values
+	for include files for packages not yet converted to LinkingTo:
+
 2014-01-16  JJ Allaiare <jj@rstudio.org>
 
         * inst/include/Rcpp/macros/macros.h: Use Rf_onintr rather than 

R/RcppLdpath.R

@@ -41,7 +41,12 @@ canUseCXX0X <- function() .Call( "canUseCXX0X", PACKAGE = "Rcpp" )
 
 ## Provide compiler flags -- i.e. -I/path/to/Rcpp.h
 RcppCxxFlags <- function(cxx0x=FALSE) {
-    ""
+    # path <- RcppLdPath()
+    path <- Rcpp.system.file( "include" )
+    if (.Platform$OS.type=="windows") {
+        path <- asBuildPath(path)
+    }
+    paste("-I", path, if (cxx0x && canUseCXX0X()) " -std=c++0x" else "", sep="")
 }
 
 ## Shorter names, and call cat() directly