* Compile on systems with C99 variable-size arrays that do not support C99
  variable declarations. Achieve this by making the check deliberately use
  C99 variable declarations.
* Add missing check for alloca.h. At least on OpenBSD, alloc() is declared in
  stdlib.h and alloc.h does not exist. Adjust libspeex/stack_alloc.h to cope.
* Declare 'int tmp;' at the beginning of the code block in libspeex/testecho.c.


git-svn-id: http://svn.xiph.org/trunk/speex@13366 0101bb08-14d6-0310-b084-bc0e0c8e3800