Merge pull request #589 from RcppCore/bugfix/issue588

correct empty return call (closes #588)

Author: jjallaire

ChangeLog

@@ -1,3 +1,6 @@
+2016-11-13  Dirk Eddelbuettel  <[email protected]>
+
+        * R/Attributes.R (mergeIntoBuildEnv): Correct 'empty' return 
 2016-11-13  Daniel C. Dillon  <[email protected]>
         * inst/include/Rcpp/RNGScope.h: Moved definition of RNGScope
         to its own file

R/Attributes.R

@@ -618,15 +618,15 @@ sourceCppFunction <- function(func, isVoid, dll, symbol) {
 
         # protect against null or empty string
         if (is.null(value) || !nzchar(value))
-            return;
+            return(invisible(NULL))
 
         # if it doesn't exist already just set it
         if (is.null(buildEnv[[name]])) {
             buildEnv[[name]] <<- value
         }
         # if it's not identical then append
         else if (!identical(buildEnv[[name]], value)) {
-            buildEnv[[name]] <<- paste(buildEnv[[name]], value);
+            buildEnv[[name]] <<- paste(buildEnv[[name]], value)
         }
         else {
             # it already exists and it's the same value, this