cppunittester: make tracking down temp file leaks easier

Temp files created before first test method don't see LO_TESTNAME

Change-Id: Iff74abf574f5151980f463646f11c1b32ad0c241

sal/cppunittester/cppunittester.cxx

@@ -237,6 +237,9 @@ public:
 #ifdef UNX
             EyecatcherListener eye;
             result.addListener(&eye);
+            // set this to track down files created before first test method
+            std::string lib(testlib.substr(testlib.rfind('/')+1));
+            setenv("LO_TESTNAME", lib.c_str(), true);
 #endif
 
             CppUnit::TestRunner runner;