Index: ChangeLog
===================================================================
--- ChangeLog	(revision 37548)
+++ ChangeLog	(working copy)
@@ -1,3 +1,14 @@
+Thu Nov  8 14:50:03 2012  Akinori MUSHA  <knu@iDaemons.org>
+
+	* include/ruby/ruby.h (alloca), eval_intern.h, gc.c: Make alloca
+	  universally work by placing the ultimate ifdef's in ruby/ruby.h.
+	  Gcc hides its builtin alloca() when -ansi is given, and build
+	  thus fails on platforms that lack their own alloca()
+	  implementation in libc, such as OpenBSD and some ports of
+	  NetBSD.
+
+	* addr2line.c (alloca): Place the ultimate ifdef's for alloca.
+
 Thu Nov  8 11:32:11 2012  Akinori MUSHA  <knu@iDaemons.org>
 
 	* configure.in (--with-opt-dir): Avoid nesting of double quotes
Index: addr2line.c
===================================================================
--- addr2line.c	(revision 37548)
+++ addr2line.c	(working copy)
@@ -32,9 +32,26 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-#if defined(HAVE_ALLOCA_H)
-#include <alloca.h>
-#endif
+/* Make alloca work the best possible way.  */
+#ifdef __GNUC__
+# ifndef atarist
+#  ifndef alloca
+#   define alloca __builtin_alloca
+#  endif
+# endif	/* atarist */
+#else
+# ifdef HAVE_ALLOCA_H
+#  include <alloca.h>
+# else
+#  ifdef _AIX
+#pragma alloca
+#  else
+#   ifndef alloca		/* predefined by HP cc +Olibcalls */
+void *alloca();
+#   endif
+#  endif /* AIX */
+# endif	/* HAVE_ALLOCA_H */
+#endif /* __GNUC__ */
 
 #ifdef HAVE_DL_ITERATE_PHDR
 # ifndef _GNU_SOURCE
Index: eval_intern.h
===================================================================
--- eval_intern.h	(revision 37548)
+++ eval_intern.h	(working copy)
@@ -31,27 +31,6 @@
 #include <crt_externs.h>
 #endif
 
-/* Make alloca work the best possible way.  */
-#ifdef __GNUC__
-# ifndef atarist
-#  ifndef alloca
-#   define alloca __builtin_alloca
-#  endif
-# endif	/* atarist */
-#else
-# ifdef HAVE_ALLOCA_H
-#  include <alloca.h>
-# else
-#  ifdef _AIX
-#pragma alloca
-#  else
-#   ifndef alloca		/* predefined by HP cc +Olibcalls */
-void *alloca();
-#   endif
-#  endif /* AIX */
-# endif	/* HAVE_ALLOCA_H */
-#endif /* __GNUC__ */
-
 #ifndef HAVE_STRING_H
 char *strrchr(const char *, const char);
 #endif
Index: gc.c
===================================================================
--- gc.c	(revision 37548)
+++ gc.c	(working copy)
@@ -65,27 +65,6 @@
 #define rb_setjmp(env) RUBY_SETJMP(env)
 #define rb_jmp_buf rb_jmpbuf_t
 
-/* Make alloca work the best possible way.  */
-#ifdef __GNUC__
-# ifndef atarist
-#  ifndef alloca
-#   define alloca __builtin_alloca
-#  endif
-# endif /* atarist */
-#else
-# ifdef HAVE_ALLOCA_H
-#  include <alloca.h>
-# else
-#  ifdef _AIX
- #pragma alloca
-#  else
-#   ifndef alloca /* predefined by HP cc +Olibcalls */
-void *alloca ();
-#   endif
-#  endif /* AIX */
-# endif /* HAVE_ALLOCA_H */
-#endif /* __GNUC__ */
-
 #ifndef GC_MALLOC_LIMIT
 #define GC_MALLOC_LIMIT 8000000
 #endif
Index: include/ruby/ruby.h
===================================================================
--- include/ruby/ruby.h	(revision 37548)
+++ include/ruby/ruby.h	(working copy)
@@ -73,13 +73,26 @@ extern "C" {
 #pragma GCC visibility push(default)
 #endif
 
-#if defined(HAVE_ALLOCA_H)
-#include <alloca.h>
+/* Make alloca work the best possible way.  */
+#ifdef __GNUC__
+# ifndef atarist
+#  ifndef alloca
+#   define alloca __builtin_alloca
+#  endif
+# endif	/* atarist */
 #else
+# ifdef HAVE_ALLOCA_H
+#  include <alloca.h>
+# else
 #  ifdef _AIX
 #pragma alloca
-#  endif
-#endif
+#  else
+#   ifndef alloca		/* predefined by HP cc +Olibcalls */
+void *alloca();
+#   endif
+#  endif /* AIX */
+# endif	/* HAVE_ALLOCA_H */
+#endif /* __GNUC__ */
 
 #if defined HAVE_UINTPTR_T && 0
 typedef uintptr_t VALUE;