diff --git a/configure.ac b/configure.ac
index 4132a81..060ad0c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -383,7 +383,7 @@ AC_DEFINE(ANSI_CPP, 1, [FIXME HARD])
 
 # The UNIX extension likes to know which of the following system calls,
 # library functions, and include files are supported by the system.
-AC_CHECK_HEADERS(utime.h sys/utime.h sys/wait.h dirent.h)
+AC_CHECK_HEADERS(utime.h sys/utime.h sys/wait.h dirent.h netdb.h)
 AC_CHECK_FUNCS(waitpid wait3 wait4 vfork uname gethostname gettimeofday ftime)
 AC_CHECK_FUNCS(mktemp tmpnam tempnam getcwd getwd rename regcomp)
 
diff --git a/lib/unix/system.c b/lib/unix/system.c
index 647843e..ecc2eed 100644
--- a/lib/unix/system.c
+++ b/lib/unix/system.c
@@ -35,6 +35,9 @@
 #if defined(HAVE_UNAME) && !defined(HAVE_GETHOSTNAME)
 #  include <sys/utsname.h>
 #endif
+#ifdef HAVE_NETDB_H
+#  include <netdb.h>
+#endif
 
 #define L_LINK_MAX     0
 #define L_NAME_MAX     1