Targets using implicit extern "C"

[E. Weddington]

Ian Lance Taylor wrote:

>Joe Buck <Joe.Buck@synopsys.COM> writes:
>
>  
>
>>On Tue, May 10, 2005 at 02:26:12PM -0400, Ian Lance Taylor wrote:
>>    
>>
>>>How would people feel about adding a configure option
>>>--with-implicit-extern-c?  Then we could justifiably flip the default
>>>for the generic *-elf, etc., targets.  In fact in general we could
>>>then take the macro out of the tm.h files and into config.gcc, which
>>>is probably a more reliable place to put it anyhow.
>>>      
>>>
>>I think that the decision should be made at configure time, by checking
>>the #include headers to see if they are C++-ready.  Look for the string
>>"__cplusplus" in some set of standard headers, if it is not found,
>>assume that we'll need implicit extern C.  For cross-builds, we still
>>have a path to the headers to be checked.
>>    
>>
>
>It would be hard to make that completely reliable for embedded systems
>development, where the header files may or not be available in any
>standard place at the time that gcc is configured.
>
>  
>
E.g. the AVR target, which normally uses avr-libc:
<http://savannah.nongnu.org/projects/avr-libc/>
but only builds avr-libc after gcc is built.

Eric