In article <200509291419.j8TEJYid015419 / moulon.inra.fr>,
  ts <decoux / moulon.inra.fr> writes:

>  Well, I've forgotten to give the reason : with bison 2.0

Hmm.  alloca is not used by default since bison 2.0.

bison-2.0/doc/bison.texinfo :
| @deffn {Macro} YYSTACK_USE_ALLOCA
| Macro used to control the use of @code{alloca} when the C
| @acronym{LALR}(1) parser needs to extend its stacks.  If defined to 0,
| the parser will use @code{malloc} to extend its stacks.  If defined to
| 1, the parser will use @code{alloca}.  Values other than 0 and 1 are
| reserved for future Bison extensions.  If not defined,
| @code{YYSTACK_USE_ALLOCA} defaults to 0.
| 
| If you define @code{YYSTACK_USE_ALLOCA} to 1, it is your
| responsibility to make sure that @code{alloca} is visible, e.g., by
| using @acronym{GCC} or by including @code{<stdlib.h>}.  Furthermore,
| in the all-too-common case where your code may run on a host with a
| limited stack and with unreliable stack-overflow checking, you should
| set @code{YYMAXDEPTH} to a value that cannot possibly result in
| unchecked stack overflow on any of your target hosts when
| @code{alloca} is called.  You can inspect the code that Bison
| generates in order to determine the proper numeric values.  This will
| require some expertise in low-level implementation details.
| @end deffn
-- 
Tanaka Akira