Re: Trailing whitespace stripped by autoconf

[Akim Demaille]

| Not sure if this has been reported yet.
| While testing a patch to gcc's configure.in, I found that a configure
| script generated by cvs autoconf (2.57a) always resulted in a failed
| test.  The configure script uses
| 
|               cat > conftest.big <<EOF
|   0000 00000010 00000000 017a0001 781a0004  .........z..x...
|   0010 00000001 00000012 00000018 00000000  ................
|   0020 00000008 04000000 0844               .........D      
|  EOF
| 
| to create a few files, then runs objdump on a compiled object
| and compares the last three lines to these files.  As such, the six
| spaces after the last 'D' are significant, as they are also generated
| by objdump.
| Now it seems that cvs autoconf trims trailing whitespace, resulting
| in incorrected test files; even surrounding the spaces with a single
| set of [] didn't help.
| This is a regression, as autoconf 2.13 DTRT here.

hi Tim,

I think this behavior was reverted.  But my own opinion here is that
you should not depend on trailing spaces, as some tools strip them.
You should use

|               sed 's/|$//' > conftest.big <<EOF
|   0000 00000010 00000000 017a0001 781a0004  .........z..x...|
|   0010 00000001 00000012 00000018 00000000  ................|
|   0020 00000008 04000000 0844               .........D      |
|  EOF

instead.  Not just to workaround Autoconf, but to avoid accidental
changes.