diff --git a/configure.ac b/configure.ac
index 8cbcfb3..3d61120 100644
--- a/configure.ac
+++ b/configure.ac
@@ -90,8 +90,8 @@ AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS([ctype.h err.h fcntl.h grp.h libintl.h limits.h \
 		  linux/magic.h linux/types.h locale.h mntent.h mqueue.h \
 		  paths.h poll.h pwd.h semaphore.h stdint.h stdlib.h string.h \
-		  strings.h sys/ioctl.h sys/mount.h sys/time.h syslog.h \
-		  time.h unistd.h])
+		  strings.h sys/ioctl.h sys/mman.h sys/mount.h sys/time.h \
+		  syslog.h time.h unistd.h])
 
 # Check /etc/mtab
 mtab_type=''
diff --git a/lib/nilfs.c b/lib/nilfs.c
index 7bb5461..906db10 100644
--- a/lib/nilfs.c
+++ b/lib/nilfs.c
@@ -54,9 +54,9 @@
 #include <limits.h>
 #endif	/* HAVE_LIMITS_H */
 
-#if HAVE_MMAP
+#if HAVE_SYS_MMAN_H
 #include <sys/mman.h>
-#endif	/* HAVE_MMAP */
+#endif	/* HAVE_SYS_MMAN_H */
 
 #if HAVE_TIME_H
 #include <time.h>