Fixes:

    gcc: numpy/random/src/xoshiro256/xoshiro256.c
    numpy/random/src/xoshiro256/xoshiro256.c:39:16: warning: comparison of integers of different signs: 'int' and 'unsigned long' [-Wsign-compare]
            for (i = 0; i < sizeof JUMP / sizeof *JUMP; i++)
                        ~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~

    gcc: numpy/random/src/xoshiro512/xoshiro512.c
    numpy/random/src/xoshiro512/xoshiro512.c:43:17: warning: comparison of integers of different signs: 'int' and 'unsigned long' [-Wsign-compare]
      for (i = 0; i < sizeof JUMP / sizeof *JUMP; i++)
                  ~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~
    numpy/random/src/xoshiro512/xoshiro512.c:46:23: warning: comparison of integers of different signs: 'int' and 'unsigned long' [-Wsign-compare]
            for (w = 0; w < sizeof s_placeholder / sizeof *s_placeholder; w++)
                        ~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    gcc: numpy/random/src/distributions/distributions.c
    numpy/random/src/distributions/distributions.c:185:14: warning: comparison of integers of different signs: 'int64_t' (aka 'long long') and 'const uint64_t' (aka 'const unsigned long long') [-Wsign-compare]
        if (rabs < ki_double[idx])
            ~~~~ ^ ~~~~~~~~~~~~~~
    numpy/random/src/distributions/distributions.c:230:14: warning: comparison of integers of different signs: 'int32_t' (aka 'int') and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
        if (rabs < ki_float[idx])
            ~~~~ ^ ~~~~~~~~~~~~~