Bug #1251

- #1251 tests should sanitize TASKDATA and TASKRC env vars (thanks to Jakub
  Wilk).

test/i18n.t.cpp

@@ -27,6 +27,7 @@
 
 #include <cmake.h>
 #include <iostream>
+#include <stdlib.h>
 #include <string>
 #include <unistd.h>
 #include <stdarg.h>
@@ -42,6 +43,10 @@ int main (int argc, char** argv)
 {
   UnitTest t (11);
 
+  // Ensure environment has no influence.
+  unsetenv ("TASKDATA");
+  unsetenv ("TASKRC");
+
   try
   {
     t.is (format ("pre {1} post",    "mid"),        "pre mid post",    "format 1a");