diff --git a/configure.ac b/configure.ac
index 94a37472..1f93cd29 100644
--- a/configure.ac
+++ b/configure.ac
@@ -36,7 +36,7 @@ LT_INIT
 dnl Checks for libraries.
 
 dnl Checks for header files.
-AC_CHECK_HEADERS(crypt.h unistd.h sys/time.h utmp.h \
+AC_CHECK_HEADERS(crypt.h sys/time.h utmp.h \
 	utmpx.h termios.h termio.h sgtty.h sys/ioctl.h syslog.h paths.h \
 	utime.h ulimit.h sys/capability.h sys/random.h sys/resource.h \
 	gshadow.h lastlog.h rpc/key_prot.h netdb.h acl/libacl.h \
diff --git a/lib/defines.h b/lib/defines.h
index 1cfc537b..db3adb3f 100644
--- a/lib/defines.h
+++ b/lib/defines.h
@@ -46,9 +46,7 @@ extern char * textdomain (const char * domainname);
 #include <sys/types.h>
 #include <sys/wait.h>
 
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#endif
+#include <unistd.h>
 
 /*
  * crypt(3), crypt_gensalt(3), and their