> C's stdlib, `math.h`, `string.h` are good but don't have string padding functions

Of course they do; how would you align printouts otherwise?

    $ cat main.c
    #include <stdio.h>
    
    int main()
    {
      (void) printf ("%42s\n", "hello");  // right-align, 42 chars
      (void) printf ("%-42s\n", "hello"); // left-align
    }
    $ gcc main.c
    $ ./a.out | cat -A                                                                                                                                                 
                                        hello$
    hello                                    $
    $ ./a.out | wc -L
    42