diff --git a/doc/fixes36.1 b/doc/fixes36.1
index 3dfa88bbb..28313a87c 100644
--- a/doc/fixes36.1
+++ b/doc/fixes36.1
@@ -637,6 +637,8 @@ PANICTRACE: PANICTRACE_GDB used wrong value for ARGV0 when launching gdb if
 win32gui: gather raw_print error messages into a single dialog window
 win32tty: fix display errors when using a font with double wide or ambiguous
 	width characters
+Amiga (untested): 'makedefs -z' didn't handle FILE_PREFIX correctly when
+	building vis_tab.h and vis_tab.c
 
 
 General New Features
diff --git a/util/makedefs.c b/util/makedefs.c
index 4d32cc4ad..f9bab0ef1 100644
--- a/util/makedefs.c
+++ b/util/makedefs.c
@@ -1,4 +1,4 @@
-/* NetHack 3.6  makedefs.c  $NHDT-Date: 1506993895 2017/10/03 01:24:55 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.117 $ */
+/* NetHack 3.6  makedefs.c  $NHDT-Date: 1516697571 2018/01/23 08:52:51 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.118 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* Copyright (c) M. Stephenson, 1990, 1991.                       */
 /* Copyright (c) Dean Luick, 1990.                                */
@@ -2816,7 +2816,7 @@ do_vision()
 #ifdef FILE_PREFIX
     Strcat(filename, file_prefix);
 #endif
-    Sprintf(filename, INCLUDE_TEMPLATE, VIS_TAB_H);
+    Sprintf(eos(filename), INCLUDE_TEMPLATE, VIS_TAB_H);
     if (!(ofp = fopen(filename, WRTMODE))) {
         perror(filename);
         exit(EXIT_FAILURE);
@@ -2839,10 +2839,15 @@ do_vision()
 #ifdef FILE_PREFIX
     Strcat(filename, file_prefix);
 #endif
-    Sprintf(filename, SOURCE_TEMPLATE, VIS_TAB_C);
+    Sprintf(eos(filename), SOURCE_TEMPLATE, VIS_TAB_C);
     if (!(ofp = fopen(filename, WRTMODE))) {
         perror(filename);
-        Sprintf(filename, INCLUDE_TEMPLATE, VIS_TAB_H);
+        /* creating vis_tab.c failed; remove the vis_tab.h we just made */
+        filename[0] = '\0';
+#ifdef FILE_PREFIX
+        Strcat(filename, file_prefix);
+#endif
+        Sprintf(eos(filename), INCLUDE_TEMPLATE, VIS_TAB_H);
         Unlink(filename);
         exit(EXIT_FAILURE);
     }