PATCH: libgomp/25877: Add alloca.h header file.

[Diego Novillo]

>	PR libgomp/25877
>	* team.c: Add include of alloca.h.
>	* configure.ac: Add check for alloca.h.
>	* configure: Regenerate.
>	* config.h.in: Regenerate.
>
>  
>
OK.