bug#10313: configure fails to find include path on openbsd

[Paul Eggert <eggert@cs.ucla.edu>]

Thanks for the bug report.  I worry that that fix,
though it works for you, may cause problmes on other
OpenBSD installations.  So I have some questions.

First, Is this use of /usr/local standardized by OpenBSD?
Is there documentation for this somewhere?

Second, gcc looks at /usr/local/include by default.  Why doesn't
that work for you?  What's the output of the following shell script
for you?  If you're not using gcc, which compiler are you using, and
can you do a similar test for it?

echo 'int main (void) { return 0; }' >t.c
gcc -v t.c

Third, why is this problem limited to /usr/local/include?
Why doesn't it also happen for /usr/local/lib?

Thanks for any further info you can provide.