Added check for sys/sysctl.h.

diff --git a/configure b/configure
index 299a97e..9c9f9d8 100755
--- a/configure
+++ b/configure
@@ -10474,6 +10474,7 @@
 
 
 
+
 for ac_header in \
 	arpa/inet.h \
 	arpa/nameser.h \
@@ -10528,6 +10529,7 @@
 	sys/statfs.h \
 	sys/strtio.h \
 	sys/syscall.h \
+	sys/sysctl.h \
 	sys/time.h \
 	sys/user.h \
 	sys/v86.h \
diff --git a/configure.ac b/configure.ac
index f831b53..d0cf587 100644
--- a/configure.ac
+++ b/configure.ac
@@ -957,6 +957,7 @@
 	sys/statfs.h \
 	sys/strtio.h \
 	sys/syscall.h \
+	sys/sysctl.h \
 	sys/time.h \
 	sys/user.h \
 	sys/v86.h \
diff --git a/include/config.h.in b/include/config.h.in
index 12f6cd8..c023d27 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -494,6 +494,9 @@
 /* Define to 1 if you have the <sys/syscall.h> header file. */
 #undef HAVE_SYS_SYSCALL_H
 
+/* Define to 1 if you have the <sys/sysctl.h> header file. */
+#undef HAVE_SYS_SYSCTL_H
+
 /* Define to 1 if you have the <sys/time.h> header file. */
 #undef HAVE_SYS_TIME_H