diff --git a/client/gui_rpc_server.C b/client/gui_rpc_server.C
index 64b2db18fa..90187acd53 100644
--- a/client/gui_rpc_server.C
+++ b/client/gui_rpc_server.C
@@ -702,10 +702,10 @@ int GUI_RPC_CONN_SET::init() {
     int one = 1;
     setsockopt(lsock, SOL_SOCKET, SO_REUSEADDR, (char*)&one, 4);
 
-    retval = bind(lsock, (const sockaddr*)(&addr), (socklen_t)sizeof(addr));
+    retval = bind(lsock, (const sockaddr*)(&addr), (boinc_socklen_t)sizeof(addr));
     if (retval) {
         addr.sin_port = htons(GUI_RPC_PORT_ALT);
-        retval = bind(lsock, (const sockaddr*)(&addr), (socklen_t)sizeof(addr));
+        retval = bind(lsock, (const sockaddr*)(&addr), (boinc_socklen_t)sizeof(addr));
         if (retval) {
             msg_printf(NULL, MSG_ERROR, "GUI RPC bind failed: %d\n", retval);
             boinc_close_socket(lsock);
@@ -778,7 +778,7 @@ bool GUI_RPC_CONN_SET::poll(double) {
     if (FD_ISSET(lsock, &read_fds)) {
         struct sockaddr_in addr;
 
-        socklen_t addr_len = sizeof(addr);
+        boinc_socklen_t addr_len = sizeof(addr);
         sock = accept(lsock, (struct sockaddr*)&addr, &addr_len);
 
         int peer_ip = (int) ntohl(addr.sin_addr.s_addr);
diff --git a/client/ssl_net_xfer.C b/client/ssl_net_xfer.C
index 7630f28fc3..490ae21249 100644
--- a/client/ssl_net_xfer.C
+++ b/client/ssl_net_xfer.C
@@ -77,13 +77,11 @@
 #include "client_msgs.h"
 
 #if defined(_WIN32) 
-typedef int socklen_t;
+typedef int boinc_socklen_t;
 #elif defined ( __APPLE__)
-typedef int32_t socklen_t;
-#elif !GETSOCKOPT_SOCKLEN_T
-#ifndef socklen_t
-typedef size_t socklen_t;
-#endif
+typedef int32_t boinc_socklen_t;
+#else
+typedef BOINC_SOCKLEN_T boinc_socklen_t;
 #endif
 
 // if an active transfer doesn't get any activity
@@ -91,7 +89,7 @@ typedef size_t socklen_t;
 #define NET_XFER_TIMEOUT    600
 
 int get_socket_error(int fd) {
-    socklen_t intsize = sizeof(int);
+    boinc_socklen_t intsize = sizeof(int);
     int n;
 #ifdef WIN32
     getsockopt(fd, SOL_SOCKET, SO_ERROR, (char *)&n, &intsize);
diff --git a/lib/network.C b/lib/network.C
index 4b558bd475..ba9c1d1ecf 100644
--- a/lib/network.C
+++ b/lib/network.C
@@ -162,7 +162,7 @@ void boinc_close_socket(int sock) {
 }
 
 int get_socket_error(int fd) {
-    socklen_t intsize = sizeof(int);
+    boinc_socklen_t intsize = sizeof(int);
     int n;
 #ifdef WIN32
     getsockopt(fd, SOL_SOCKET, SO_ERROR, (char *)&n, &intsize);
diff --git a/lib/network.h b/lib/network.h
index ebfe3fade5..cf91e3a146 100644
--- a/lib/network.h
+++ b/lib/network.h
@@ -16,6 +16,8 @@
 // http://www.gnu.org/copyleft/lesser.html
 // or write to the Free Software Foundation, Inc.,
 // 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#ifndef _BOINC_NETWORK_H_
+#define _BOINC_NETWORK_H_
 
 extern int resolve_hostname(char* hostname, int& ip_addr, char* msg);
 extern int boinc_socket(int& sock);
@@ -24,12 +26,12 @@ extern void boinc_close_socket(int sock);
 extern int get_socket_error(int fd);
 
 #if defined(_WIN32)
-typedef int socklen_t;
+typedef int boinc_socklen_t;
 #define SHUT_WR SD_SEND
 #elif defined( __APPLE__)
-typedef int32_t socklen_t;
-#elif !defined(GETSOCKOPT_SOCKLEN_T) && !defined(_SOCKLEN_T_DECLARED) && !defined(socklen_t)
-typedef size_t socklen_t;
+typedef int32_t boinc_socklen_t;
+#else
+typedef BOINC_SOCKLEN_T boinc_socklen_t;
 #endif
 
 #define CONNECTED_STATE_NOT_CONNECTED   0
@@ -45,3 +47,4 @@ extern int  NetOpen();
 extern void NetClose();
 extern void NetCheck(bool hangup_if_dialed);
 #endif
+#endif
diff --git a/m4/boinc_getsockopt.m4 b/m4/boinc_getsockopt.m4
index c03a145dde..a7f8646128 100644
--- a/m4/boinc_getsockopt.m4
+++ b/m4/boinc_getsockopt.m4
@@ -1,16 +1,66 @@
 
 AC_DEFUN([BOINC_GETSOCKOPT_TYPE],[
-dnl TODO: use compiler to test these; there probably exists an autoconf macro already!
-AC_MSG_CHECKING(type of getsockopt() parameter four)
-case "$target" in
-*-linux* | *solaris* | *openbsd* )
-        AC_DEFINE(GETSOCKOPT_SOCKLEN_T, 1, [getsockopt uses socklen_t])
-	AC_MSG_RESULT(socklen_t)
-        ;;
-*sysv5OpenUNIX8* | *hpux* | i*86*cygwin* )
-        AC_DEFINE(GETSOCKOPT_SIZE_T, 1, [getsockopt uses size_t])
-	AC_MSG_RESULT(size_t)
-        ;;
-esac
+AC_LANG_PUSH(C)
+AC_CHECK_HEADERS([sys/socket.h])
+if test "${ac_cv_header_sys_socket_h}" = "yes" ; then
+  ac_includes_default="${ac_includes_default}
+#include <sys/socket.h>
+"
+fi
+AC_CHECK_TYPES([socklen_t]) 
+B_SV_CFLAGS="${CFLAGS}"
+if test "${ac_cv_c_compiler_gnu}" = "yes" ; then
+  CFLAGS="${CFLAGS} -Werror -pedantic"
+fi
+AC_CACHE_CHECK([type of getsockopt() parameter five],
+[boinc_cv_getsockopt_type],
+[
+  if test "${ac_cv_type_socklen_t}" = "yes" ; then
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+#define CONFIG_TEST
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+      ]],
+      [
+        socklen_t l;
+        return getsockopt(0,0,0,(void *)0,&l);
+      ])],
+      [
+        boinc_cv_getsockopt_type="socklen_t"
+      ]
+    )
+  fi
+  if test -z "${boinc_cv_getsockopt_type}"; then
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+#define CONFIG_TEST
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+      ]],
+      [
+        size_t l;
+        return getsockopt(0,0,0,(void *)0,&l);
+      ])],
+      [
+        boinc_cv_getsockopt_type="size_t"
+      ],
+      [
+        boinc_cv_getsockopt_type="int"
+      ]
+    )
+  fi
+])
+CFLAGS="${B_SV_CFLAGS}"
+AC_DEFINE_UNQUOTED([BOINC_SOCKLEN_T],[${boinc_cv_getsockopt_type}],[Define to the type pointed to by the 5th parameter of getsockopt])
+AC_LANG_POP(C)
 ])