* configure.in, hash.c (ruby_setenv): use setenv(3) and unsetenv(3)

where they are supported. modifing environ variable seems to
  segfault solaris 10. [ruby-core:7276] [ruby-dev:28270]

* ruby.c (set_arg0): if use setenv(3), environ space cannot be used
  for altering argv[0].


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@9868 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -8,7 +8,7 @@ Tue Jan 31 11:58:51 2006  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
 Tue Jan 31 00:10:26 2006  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
 
 	* ext/syck/rubyext.c (syck_resolver_transfer): workaround for SEGV.
-	  ex: YAML.load("!map:B {}"). [ruby-core:7217]
+	  ex: ruby -ryaml -e 'YAML.load("!map:B {}")' [ruby-core:7217]
 
 Sat Jan 28 07:56:57 2006  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
 

configure.in

@@ -444,7 +444,7 @@ AC_CHECK_FUNCS(fmod killpg wait4 waitpid syscall chroot fsync getcwd eaccess\
 	      lchown lchmod getpgrp setpgrp getpgid setpgid initgroups\
 	      getgroups setgroups getpriority getrlimit dlopen sigprocmask\
 	      sigaction _setjmp setsid telldir seekdir fchmod mktime timegm\
-	      cosh sinh tanh setuid setgid)
+	      cosh sinh tanh setuid setgid setenv unsetenv)
 AC_ARG_ENABLE(setreuid,
        [  --enable-setreuid       use setreuid()/setregid() according to need even if obsolete.],
        [use_setreuid=$enableval])

hash.c

@@ -1812,7 +1812,7 @@ ruby_setenv(name, value)
      *         RTL's environ global variable directly yet.
      */
     SetEnvironmentVariable(name,value);
-#elif defined __CYGWIN__
+#elif defined(HAVE_SETENV) && defined(HAVE_UNSETENV)
 #undef setenv
 #undef unsetenv
     if (value)

ruby.c

@@ -971,7 +971,14 @@ VALUE rb_progname;
 VALUE rb_argv;
 VALUE rb_argv0;
 
-#if !defined(PSTAT_SETCMD) && !defined(HAVE_SETPROCTITLE) && !defined(DOSISH)
+#if defined(PSTAT_SETCMD) || defined(HAVE_SETPROCTITLE)
+#elif defined(_WIN32)
+#elif defined(HAVE_SETENV) && defined(HAVE_UNSETENV)
+#else
+#define USE_ENVSPACE_FOR_ARG0
+#endif
+
+#ifdef USE_ENVSPACE_FOR_ARG0
 static struct {
     char *begin, *end;
 } envspace;
@@ -1047,7 +1054,7 @@ set_arg0(val, id)
 		break;
 	    }
 	}
-#ifndef DOSISH
+#if defined(USE_ENVSPACE_FOR_ARG0)
 	if (s + 1 == envspace.begin) {
 	    s = envspace.end;
 	    ruby_setenv("", NULL); /* duplicate environ vars */