Re: mmapping of /dev/zero always fails on darwin

[Bruno Haible]

Derek Price wrote:
> Generally, I choose to be pessimistic about test failures when
> cross-compiling.  Anyone have an opinion about whether I should be
> pessimistic always or just when the target system name matches gcc's
> list of systems which fail this test?

Generally, I try to use this approach:
  1) Attempt to determine the presence of a feature/bug precisely, by running
     a test program if needed.
  2) When cross-compiling, try to approximate the decision through some
     #ifdefs or   case $host ... test.
     Don't be pessimistic always.

Reason for 1): This gives an incent to the vendors to add the features or
fix the bugs. If you always exclude some feature on, say, HP-UX, you will
not take advantage if it's fixed in HP-UX 12.

Reason for 2): Cross-compilation is quite frequent in the Linux camp.
(That was actually the original market of cygnus.com.) Don't penalize them.
On the other hand, you probably don't need to care about people cross-
compiling to NetBSD or AIX - hardly anyone does this.

Bruno