Bug #1251

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

test/path.t.cpp

@@ -26,6 +26,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include <cmake.h>
+#include <stdlib.h>
 #include <Context.h>
 #include <Path.h>
 #include <Directory.h>
@@ -37,6 +38,10 @@ int main (int argc, char** argv)
 {
   UnitTest t (32);
 
+  // Ensure environment has no influence.
+  unsetenv ("TASKDATA");
+  unsetenv ("TASKRC");
+
   // Path ();
   Path p0;
   t.is (p0._data, "", "Path::Path");