cmList: Add container conversion to string

Source/cmExportBuildFileGenerator.cxx

@@ -19,6 +19,7 @@
 #include "cmGeneratorExpression.h"
 #include "cmGeneratorTarget.h"
 #include "cmGlobalGenerator.h"
+#include "cmList.h"
 #include "cmLocalGenerator.h"
 #include "cmMakefile.h"
 #include "cmMessageType.h"
@@ -237,7 +238,7 @@ void cmExportBuildFileGenerator::SetImportLocationProperty(
     }
 
     // Store the property.
-    properties[prop] = cmJoin(objects, ";");
+    properties[prop] = cmList::to_string(objects);
   } else {
     // Add the main target file.
     {