socket: fix build error and warnings on mingw

* ext/socket/extconf.rb: check for if_nametoindex() for
  i686-w64-mingw32, and check for declarations of if_indextoname() and
  if_nametoindex().
* ext/socket/ifaddr.c (ifaddr_ifindex): not-implement unless
  if_nametoindex() is available.
* ext/socket/rubysocket.h: declare if_indextoname() and
  if_nametoindex() if available but not declared.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40738 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,15 @@
+Tue May 14 23:24:31 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/socket/extconf.rb: check for if_nametoindex() for
+	  i686-w64-mingw32, and check for declarations of if_indextoname() and
+	  if_nametoindex().
+
+	* ext/socket/ifaddr.c (ifaddr_ifindex): not-implement unless
+	  if_nametoindex() is available.
+
+	* ext/socket/rubysocket.h: declare if_indextoname() and
+	  if_nametoindex() if available but not declared.
+
 Tue May 14 19:58:17 2013  CHIKANAGA Tomoyuki  <nagachika@ruby-lang.org>
 
 	* ext/dl/lib/dl/func.rb (DL::Function#call): check tainted when

ext/socket/extconf.rb

@@ -421,7 +421,20 @@ EOF
 
   have_func("getpeerucred(0, (ucred_t **)NULL)", headers) # SunOS
 
-  have_func('if_indextoname(0, "")', headers)
+  have_func_decl = proc do |name, headers|
+    if !checking_for("declaration of #{name}()") {!%w[int void].all? {|ret| try_compile(<<EOF)}}
+#{cpp_include(headers)}
+#{ret} #{name}(void);
+EOF
+      $defs << "-DNEED_#{name.tr_cpp}_DECL"
+    end
+  end
+  if have_func('if_indextoname(0, "")', headers)
+    have_func_decl["if_indextoname"]
+  end
+  if have_func('if_nametoindex("")', headers)
+    have_func_decl["if_nametoindex"]
+  end
 
   have_func("hsterror", headers)
   have_func('getipnodebyname("", 0, 0, (int *)0)', headers) # RFC 2553

ext/socket/ifaddr.c

@@ -135,6 +135,7 @@ ifaddr_name(VALUE self)
  * Returns the interface index of _ifaddr_.
  */
 
+#ifdef HAVE_IF_NAMETOINDEX
 static VALUE
 ifaddr_ifindex(VALUE self)
 {
@@ -146,6 +147,9 @@ ifaddr_ifindex(VALUE self)
     }
     return UINT2NUM(ifindex);
 }
+#else
+#define ifaddr_ifindex rb_f_notimplement
+#endif
 
 /*
  * call-seq:

ext/socket/rubysocket.h

@@ -106,6 +106,13 @@
 typedef int socklen_t;
 #endif
 
+#ifdef NEED_IF_INDEXTONAME_DECL
+char *if_indextoname(unsigned int, char *);
+#endif
+#ifdef NEED_IF_NAMETOINDEX_DECL
+unsigned int if_nametoindex(const char *);
+#endif
+
 #define SOCKLEN_MAX \
   (0 < (socklen_t)-1 ? \
    ~(socklen_t)0 : \