Autoconf 2.59 breaks libstdc++ checks

[Andrew Haley]

Gunther Nikl writes:
 > On Thu, May 06, 2004 at 01:09:07AM +0200, Andreas Schwab wrote:
 > > Kean Johnston <jkj@sco.com> writes:
 > > 
 > > > The problem is the new code there does a #undef $1. This is
 > > > what is breaking things, and its wrong. It is a perfectly
 > > > valid thing for an OS to use #define to implement some function
 > > > in terms of another.
 > > 
 > > But unless stated otherwise, all functions in the C library are also
 > > required to be provided as indentifiers with external linkage.
 > 
 >   What about getc, putc and putchar from stdio? The man page from FreeBSD
 >   states these are macros. I am getting linker errors because libstdc++.a
 >   has references to getc/putc but both exist as macro only (an ANSI/ISO C
 >   library on AmigaOS).

Then that AmigaOS ANSI/ISO C library is broken.  If you look at
Section 7.1.4, "Use of library functions", you'll see that it's legal
for a program to use "#undef getc" to ensure that an actual function
is available for getc.

Andrew.