Re: [PATCH]: Fix PR bootstrap/29402 parallel make bug

[DJ Delorie <dj at redhat dot com>]

> Maybe using awk to split lines would be better, i.e.:
> 
> awk '{for(x=1;x<=NF;x++)print$x}'
> 
> We can use AC_PROG_AWK to find awk.  The gcc/configure.ac already errors
> if there is no system awk.

That's fine for gcc itself, but I was thinking of a tool that could be
used anywhere in the build tree, including the toplevel.  Might as
well start avoiding the shell issues completely.

> I assume you mean write a C program to do this?

Yes.

> That seems like a lot of effort to me

What, one call to qsort and a loop with a strcmp in it?  That replaces
a number of other commands, and removes any trace of unportability.

Hmm... goes gnu make have these features?  Meaning, sort and unique?

> unless you already have something hidden away in your back pocket...

Well, DJGPP has a helper already, but I'm not sure how much that helps
the gcc build system.

> To me, using awk would avoid "bizarre shell-isms".  It's clear and simple.
> What do you think?

By bizzare shell-isms, I mean the echo/backtick/variable/sort/sed/uniq
hacks that where there just to remove duplicates from a list.

This is "misc.c" from djgpp, which does the few things that are hard
to do portably, just as an example:

/* Copyright (C) 1997 DJ Delorie, see COPYING.DJ for details */
#include <stdio.h>
#include <unistd.h>

/* Miscellaneous things that are hard to do the same
   between Unix and MS-DOS */

int
main(int argc, char **argv)
{
  /* MS-DOS uses \, unix uses / */
  if (argc > 2 && strcmp(argv[1], "mkdir") == 0)
    mkdir(argv[2], 0777);

  /* redirection and long command lines don't always
     mix well under MS-DOS */
  if (argc > 2 && strcmp(argv[1], "echo") == 0)
  {
    FILE *f;
    int i;
    if (strcmp(argv[2], "-") == 0)
      f = stdout;
    else
    {
      f = fopen(argv[2], "w");
      if (f == 0)
      {
	perror(argv[2]);
	exit(1);
      }
    }
    if (f == 0)
    {
      perror(argv[2]);
      exit(1);
    }
    for (i=3; i<argc; i++)
    {
      if (i > 3) fputc(' ', f);
      fputs(argv[i], f);
    }
    fputc('\n', f);
    fflush(f);
    if (f != stdout)
      fclose(f);
  }

  /* copy \ vs cp / */
  if (argc > 3 && strcmp(argv[1], "cp") == 0)
  {
    FILE *in, *out;
    int c;
    in = fopen(argv[2], "rb");
    if (!in) {
      printf("misc: cp: can't read from %s\n", argv[2]);
      exit(1);
    }
    out = fopen(argv[3], "wb");
    if (!out) {
      printf("misc: cp: can't write to %s\n", argv[3]);
      exit(1);
    }
    while ((c = fgetc(in)) != EOF)
      fputc(c, out);
    fclose(in);
    fclose(out);
  }

  /* erase \ vs rm / */
  if (argc > 2 && strcmp(argv[1], "rm") == 0)
  {
    int i;
    for (i=2; i<argc; i++)
      unlink(argv[i]);
  }

  /* No args, just like "true" which MS-DOS doesn't have */
  return 0;
}