travis.ci: enable ctest_output_on_failure

Gabriele Contini

2020-04-26 ab6323d5603413c8dc4db27401402008a13a9805

 test/library/CMakeLists.txt

@@ -14,7 +14,7 @@
ELSE(WIN32)
    add_executable(
       test_os_linux
       Os_Linux_test.cpp
       os_linux_test.cpp
   )

   target_link_libraries(