diff --git a/include/cstd.h b/include/cstd.h
index 10951d1d2..9a22651f6 100644
--- a/include/cstd.h
+++ b/include/cstd.h
@@ -54,6 +54,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <signal.h>
+#include <assert.h>
 
 #endif /* !__cplusplus */
 #endif /* CSTD_H */
diff --git a/src/light.c b/src/light.c
index 43701ed00..85c2beb2c 100644
--- a/src/light.c
+++ b/src/light.c
@@ -3,7 +3,6 @@
 /* NetHack may be freely redistributed.  See license for details.       */
 
 #include "hack.h"
-#include <assert.h>
 
 /*
  * Mobile light sources.
diff --git a/src/mklev.c b/src/mklev.c
index 6b5ec0eb0..61c9b8d77 100644
--- a/src/mklev.c
+++ b/src/mklev.c
@@ -4,7 +4,6 @@
 /* NetHack may be freely redistributed.  See license for details. */
 
 #include "hack.h"
-#include <assert.h>
 
 /* for UNIX, Rand #def'd to (long)lrand48() or (long)random() */
 /* croom->lx etc are schar (width <= int), so % arith ensures that */
diff --git a/src/vision.c b/src/vision.c
index 546061c80..018a1ec1e 100644
--- a/src/vision.c
+++ b/src/vision.c
@@ -3,7 +3,6 @@
 /* NetHack may be freely redistributed.  See license for details.       */
 
 #include "hack.h"
-#include <assert.h>
 
 /* Circles
  * ==================================================================*/