Fix for alloca() usage

[address@hidden]

Hello,
the following files:

libguile/control.c
libguile/fluids.c
libguile/foreign.c
libguile/hashtab.c
libguile/strings.c

require to include <alloca.h>.
Since the alloca.h generated into the /lib directory takes care of various 
configurations, this will fix alloca() usage: after applying the fix, these 
sources will be able to be compiled on Windows since the compiler implements 
_alloca() instead of alloca().
The attached patch has been generated from the latest sources in the 
repository.

Sincerely,

Carlo Bramini.

guile.txt
Description: Text document