perf-urgent-2020-03-15

  - AMD uncore driver:

    Replace the open coded sanity check with the core variant, which
    provides the correct error code and also leaves a hint in dmesg

  - tools:

    - Fix the stdio input handling with glibc versions >= 2.28

    - Unbreak the futex-wake benchmark which was reduced to 0 test threads
      due to the conversion to cpumaps

    - Initialize sigaction structs before invoking sys_sigactio()

    - Plug the mapfile memory leak in perf jevents

    - Fix off by one relative directory includes

    - Fix an undefined string comparison in perf diff