diff --git a/configure.in b/configure.in
index 602cb1d56..31ed85bd0 100644
--- a/configure.in
+++ b/configure.in
@@ -515,9 +515,6 @@ AC_SUBST([SCM_I_GSC_T_UINTMAX])
 AC_SUBST([SCM_I_GSC_NEEDS_STDINT_H])
 AC_SUBST([SCM_I_GSC_NEEDS_INTTYPES_H])
 
-AC_CHECK_TYPE(socklen_t, int)
-AC_CHECK_TYPE(struct ip_mreq)
-
 AC_HEADER_STDC
 AC_HEADER_DIRENT
 AC_HEADER_TIME
@@ -532,6 +529,18 @@ sys/time.h sys/timeb.h sys/times.h sys/stdtypes.h sys/types.h \
 sys/utime.h time.h unistd.h utime.h pwd.h grp.h sys/utsname.h \
 direct.h])
 
+# On MacOS X <sys/socklen.h> contains socklen_t, so must include that
+# when testing.
+AC_CHECK_TYPE(socklen_t, ,
+  [AC_DEFINE_UNQUOTED(socklen_t, int,
+                      [Define to `int' if <sys/socket.h> does not define.])],
+  [#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#include <sys/socket.h>
+])
+AC_CHECK_TYPE(struct ip_mreq)
+
 GUILE_HEADER_LIBC_WITH_UNISTD
 
 AC_TYPE_GETGROUPS