diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 8c6ff8e6efc..58a85348683 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -20,6 +20,9 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <unistd.h>
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 
 #include "libpq/auth.h"
 #include "libpq/crypt.h"
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 3ee2c07adc2..86b6c4ce6f7 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -34,6 +34,9 @@
 #ifdef HAVE_SYS_POLL_H
 #include <sys/poll.h>
 #endif
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 
 #include "pgstat.h"
 
diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
index c78b7ec8853..44da062ea17 100644
--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@@ -18,7 +18,9 @@
 #include <unistd.h>
 #include <dirent.h>
 #include <sys/stat.h>
-
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 #ifdef HAVE_LIBZ
 #include <zlib.h>
 #endif
diff --git a/src/port/pgsleep.c b/src/port/pgsleep.c
index 988bfb05db1..867cf9bf411 100644
--- a/src/port/pgsleep.c
+++ b/src/port/pgsleep.c
@@ -14,6 +14,9 @@
 
 #include <unistd.h>
 #include <sys/time.h>
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 
 /*
  * In a Windows backend, we don't use this implementation, but rather
diff --git a/src/test/examples/testlibpq2.c b/src/test/examples/testlibpq2.c
index 850993f6e82..07c6317a212 100644
--- a/src/test/examples/testlibpq2.c
+++ b/src/test/examples/testlibpq2.c
@@ -34,6 +34,10 @@
 #include <errno.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
 #include "libpq-fe.h"
 
 static void