merges r20341 from trunk into ruby_1_9_1.

* signal.c (register_sigaltstack): should not add external
  variable (with some cosmetic changes).  [ruby-dev:37158]

git-svn-id: http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_1@20404 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon Nov 24 23:16:32 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* signal.c (register_sigaltstack): should not add external
+	  variable (with some cosmetic changes).  [ruby-dev:37158]
+
 Mon Nov 24 22:57:25 2008  Shugo Maeda  <shugo@ruby-lang.org>
 
 	* strftime.c (rb_strftime): A width specifier for %t and %n should

signal.c

@@ -47,11 +47,6 @@ typedef int rb_atomic_t;
 # define NSIG (_SIGMAX + 1)      /* For QNX */
 #endif
 
-#if defined(SIGSEGV) && defined(HAVE_SIGALTSTACK)
-#define USE_SIGALTSTACK
-int is_altstack_defined = 0;
-#endif
-
 static const struct signals {
     const char *signm;
     int  signo;
@@ -415,21 +410,28 @@ static struct {
 typedef RETSIGTYPE (*sighandler_t)(int);
 
 #ifdef POSIX_SIGNAL
+#if defined(SIGSEGV) && defined(HAVE_SIGALTSTACK)
+#define USE_SIGALTSTACK
+#endif
+
 #ifdef USE_SIGALTSTACK
 #ifdef SIGSTKSZ
 #define ALT_STACK_SIZE SIGSTKSZ
 #else
 #define ALT_STACK_SIZE (4*1024)
 #endif
 /* alternate stack for SIGSEGV */
-static void register_sigaltstack() {
+static void
+register_sigaltstack()
+{
+    static int is_altstack_defined = 0;
     stack_t newSS, oldSS;
 
-    if(is_altstack_defined)
+    if (is_altstack_defined)
       return;
 
     newSS.ss_sp = malloc(ALT_STACK_SIZE);
-    if(newSS.ss_sp == NULL)
+    if (newSS.ss_sp == NULL)
       /* should handle error */
        rb_bug("register_sigaltstack. malloc error\n");
     newSS.ss_size = ALT_STACK_SIZE;