unit-tests: Allow default test timeout to be configured via compile option

Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>

src/libstrongswan/tests/test_suite.h

@@ -39,7 +39,9 @@ typedef struct test_fixture_t test_fixture_t;
 /**
  * Default timeout for a single test function
  */
+#ifndef TEST_FUNCTION_DEFAULT_TIMEOUT
 #define TEST_FUNCTION_DEFAULT_TIMEOUT 2
+#endif
 
 /**
  * Test function implementation