diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7108d04d..01c1c5d1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -186,6 +186,7 @@ CARES_FUNCTION_IN_LIBRARY (clock_gettime rt HAVE_LIBRT)
 
 
 # Look for necessary includes
+CHECK_INCLUDE_FILES (AvailabilityMacros.h  HAVE_AVAILABILITYMACROS_H)
 CHECK_INCLUDE_FILES (sys/types.h           HAVE_SYS_TYPES_H)
 CHECK_INCLUDE_FILES (sys/random.h          HAVE_SYS_RANDOM_H)
 CHECK_INCLUDE_FILES (sys/socket.h          HAVE_SYS_SOCKET_H)
@@ -300,6 +301,7 @@ MACRO (CARES_EXTRAINCLUDE_IFSET var include)
 	ENDIF ()
 ENDMACRO ()
 
+CARES_EXTRAINCLUDE_IFSET (HAVE_AVAILABILITYMACROS_H AvailabilityMacros.h)
 CARES_EXTRAINCLUDE_IFSET (HAVE_STDBOOL_H      stdbool.h)
 CARES_EXTRAINCLUDE_IFSET (HAVE_SYS_TYPES_H    sys/types.h)
 CARES_EXTRAINCLUDE_IFSET (HAVE_ARPA_INET_H    arpa/inet.h)
@@ -633,9 +635,6 @@ ENDIF ()
 IF (HAVE_SYS_TYPES_H)
 	SET (CARES_HAVE_SYS_TYPES_H 1)
 ENDIF ()
-IF (HAVE_SYS_RANDOM_H)
-	SET (CARES_HAVE_SYS_RANDOM_H 1)
-ENDIF()
 IF (HAVE_SYS_SOCKET_H)
 	SET (CARES_HAVE_SYS_SOCKET_H 1)
 ENDIF()
diff --git a/configure.ac b/configure.ac
index 9a119e04..84df1966 100644
--- a/configure.ac
+++ b/configure.ac
@@ -409,6 +409,7 @@ dnl check for a few basic system headers we need
 AC_CHECK_HEADERS(
        malloc.h \
        memory.h \
+       AvailabilityMacros.h \
        sys/types.h \
        sys/time.h \
        sys/select.h \
@@ -469,6 +470,9 @@ dnl *Sigh* these are needed in order for net/if.h to get properly detected.
 cares_all_includes="
 #include <stdio.h>
 #include <stdlib.h>
+#ifdef HAVE_AVAILABILITYMACROS_H
+#  include <AvailabilityMacros.h>
+#endif
 #ifdef HAVE_SYS_UIO_H
 #  include <sys/uio.h>
 #endif
@@ -756,9 +760,6 @@ dnl ares_build.h.in specific defines
 if test "x$ac_cv_header_sys_types_h" = "xyes" ; then
   CARES_DEFINE_UNQUOTED([CARES_HAVE_SYS_TYPES_H],[1])
 fi
-if test "x$ac_cv_header_sys_random_h" = "xyes" ; then
-  CARES_DEFINE_UNQUOTED([CARES_HAVE_SYS_RANDOM_H],[1])
-fi
 if test "x$ac_cv_header_sys_socket_h" = "xyes" ; then
   CARES_DEFINE_UNQUOTED([CARES_HAVE_SYS_SOCKET_H],[1])
 fi
diff --git a/include/ares_build.h.cmake b/include/ares_build.h.cmake
index e2ab7173..da8a7e06 100644
--- a/include/ares_build.h.cmake
+++ b/include/ares_build.h.cmake
@@ -12,7 +12,6 @@
  * files.  We need to include some dependent headers that may be system specific
  * for C-Ares */
 #cmakedefine CARES_HAVE_SYS_TYPES_H
-#cmakedefine CARES_HAVE_SYS_RANDOM_H
 #cmakedefine CARES_HAVE_SYS_SOCKET_H
 #cmakedefine CARES_HAVE_WINDOWS_H
 #cmakedefine CARES_HAVE_WS2TCPIP_H
@@ -25,10 +24,6 @@
 #  include <sys/types.h>
 #endif
 
-#ifdef CARES_HAVE_SYS_RANDOM_H
-#  include <sys/random.h>
-#endif
-
 #ifdef CARES_HAVE_SYS_SOCKET_H
 #  include <sys/socket.h>
 #endif
diff --git a/include/ares_build.h.in b/include/ares_build.h.in
index b4a26d89..e55b39b0 100644
--- a/include/ares_build.h.in
+++ b/include/ares_build.h.in
@@ -12,7 +12,6 @@
  * files.  We need to include some dependent headers that may be system specific
  * for C-Ares */
 #undef CARES_HAVE_SYS_TYPES_H
-#undef CARES_HAVE_SYS_RANDOM_H
 #undef CARES_HAVE_SYS_SOCKET_H
 #undef CARES_HAVE_WINDOWS_H
 #undef CARES_HAVE_WS2TCPIP_H
@@ -25,10 +24,6 @@
 #  include <sys/types.h>
 #endif
 
-#ifdef CARES_HAVE_SYS_RANDOM_H
-#  include <sys/random.h>
-#endif
-
 #ifdef CARES_HAVE_SYS_SOCKET_H
 #  include <sys/socket.h>
 #endif
diff --git a/src/lib/ares_config.h.cmake b/src/lib/ares_config.h.cmake
index 4529eb94..da64de04 100644
--- a/src/lib/ares_config.h.cmake
+++ b/src/lib/ares_config.h.cmake
@@ -182,6 +182,9 @@
 /* Define to 1 if you have the memory.h header file. */
 #cmakedefine HAVE_MEMORY_H
 
+/* Define to 1 if you have the AvailabilityMacros.h header file. */
+#cmakedefine HAVE_AVAILABILITYMACROS_H
+
 /* Define to 1 if you have the MSG_NOSIGNAL flag. */
 #cmakedefine HAVE_MSG_NOSIGNAL
 
diff --git a/src/lib/ares_rand.c b/src/lib/ares_rand.c
index 976d8ff6..a7a74c9a 100644
--- a/src/lib/ares_rand.c
+++ b/src/lib/ares_rand.c
@@ -28,6 +28,13 @@
 #include "ares.h"
 #include "ares_private.h"
 #include <stdlib.h>
+
+/* Older MacOS versions require including AvailabilityMacros.h before
+ * sys/random.h */
+#ifdef HAVE_AVAILABILITYMACROS_H
+#  include <AvailabilityMacros.h>
+#endif
+
 #ifdef HAVE_SYS_RANDOM_H
 #  include <sys/random.h>
 #endif
diff --git a/src/lib/setup_once.h b/src/lib/setup_once.h
index 042a3aae..8341b348 100644
--- a/src/lib/setup_once.h
+++ b/src/lib/setup_once.h
@@ -95,10 +95,6 @@
 #  endif
 #endif
 
-#ifdef HAVE_SYS_RANDOM_H
-#  include <sys/random.h>
-#endif
-
 #ifdef HAVE_SYS_SOCKET_H
 #  include <sys/socket.h>
 #endif