Re: CFLAGS for AC_COMPILE_IFELSE.

[Daniel E. Macks]

Ralf Corsepius <address@hidden> said:
> On Tue, 2008-05-13 at 13:11 -0500, Bob Friesenhahn wrote:
>> On Tue, 13 May 2008, Ralf Corsepius wrote:
>> >
>> > /usr/include (and /usr/lib) + /usr/local/include (and /usr/local/lib)
>> > are special to GCC, they are on the system-default (include, library)
>> > search paths, and are treated differently than other directories by GCC
>> 
>> More often than not, the formally installed GCC ignores 
>> /usr/local/include.  For example, the GCC that comes with OS-X Leopard 
>> does not look there.  The GCC that comes with FreeBSD 7.0 does not 
>> look there.  On the other hand, the 'cc' that came with SunOS 4.1.3 
>> does check /usr/local/include by default, so the GCC install for that 
>> target did check /usr/local/include by default so that it would match 
>> the system compiler.  It should not be assumed that if the compiler is 
>> GCC that it will pay any attention to /usr/local/include.
> Vendor supplied "cc"s (traditionally closed source), traditionally don't
> look into /usr/local/include.
>
> FSF-GCC's do, because they treat /usr/local/{lib/include} as the
> directories to put files into which are supposed to replace vendor
> supplied files.
>
> That said, the behavior you describe for OS-X's cc doesn't surprise me,
> but I can't find FreeBSD's  behavior helpful.

OS X has always looked in /usr/local, both according to its
documentation and its runtime functionality (just checked a 10.4 box
with apple's normal XCode suite for that system installed).

dan

-- 
Daniel Macks
address@hidden
http://www.netspace.org/~dmacks