regex: stop using alloca

It syncs with gnulib version 87ed1f9c4.  No functional changes is
expected.

Checked on x86_64-linux-gnu.

diff --git a/posix/regex_internal.h b/posix/regex_internal.h
index 011f73317675f7acbc06cf078230fd3bfaa6ef99..edcdc07e999694aca9e1ca89f3af71ab874c4ee3 100644 (file)
--- a/posix/regex_internal.h
+++ b/posix/regex_internal.h
@@ -444,25 +444,6 @@ typedef struct re_dfa_t re_dfa_t;
 #define re_string_skip_bytes(pstr,idx) ((pstr)->cur_idx += (idx))
 #define re_string_set_index(pstr,idx) ((pstr)->cur_idx = (idx))
 
-#if defined _LIBC || HAVE_ALLOCA
-# include <alloca.h>
-#endif
-
-#ifndef _LIBC
-# if HAVE_ALLOCA
-/* The OS usually guarantees only one guard page at the bottom of the stack,
-   and a page size can be as small as 4096 bytes.  So we cannot safely
-   allocate anything larger than 4096 bytes.  Also care for the possibility
-   of a few compiler-allocated temporary stack slots.  */
-#  define __libc_use_alloca(n) ((n) < 4032)
-# else
-/* alloca is implemented with malloc, so just use malloc.  */
-#  define __libc_use_alloca(n) 0
-#  undef alloca
-#  define alloca(n) malloc (n)
-# endif
-#endif
-
 #ifdef _LIBC
 # define MALLOC_0_IS_NONNULL 1
 #elif !defined MALLOC_0_IS_NONNULL