Re: CFLAGS for AC_COMPILE_IFELSE.

[Ralf Corsepius]

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.

Ralf