merges r21505 from trunk into ruby_1_9_1.

* ext/socket/extconf.rb (gai_strerror): checks if available and if
  returns const pointer.

* ext/socket/getaddrinfo.c (gai_strerror): defines only if non
  available.  [ruby-core:21328]

git-svn-id: http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_1@21558 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 13 insertions, 0 deletions

diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index 06011d61a..99deaf879 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -254,6 +254,19 @@ unless getaddr_info_ok and have_func("getnameinfo", headers) and have_func("geta
   have_func("inet_ntop") or have_func("inet_ntoa")
   have_func("inet_pton") or have_func("inet_aton")
   have_func("getservbyport")
+  if have_func("gai_strerror")
+    unless checking_for("gai_strerror() returns const pointer") {!try_compile(<<EOF)}
+#{cpp_include(headers)}
+#include <stdlib.h>
+void
+conftest_gai_strerror_is_const()
+{
+    *gai_strerror(0) = 0;
+}
+EOF
+      $defs << "-DGAI_STRERROR_CONST"
+    end
+  end
   have_header("arpa/nameser.h")
   have_header("resolv.h")
 end