--- Yap-5.1.3.orig/console/yap.c	2008-06-05 01:58:37.000000000 +1200
+++ Yap-5.1.3/console/yap.c	2008-08-24 14:31:21.000000000 +1200
@@ -82,6 +82,7 @@
 static int output_msg;
 #endif
 
+static char *YapBootDir = NULL;
 static char BootFile[] = "boot.yap";
 static char InitFile[] = "init.yap";
 
@@ -595,11 +596,22 @@
   BootMode = parse_yap_arguments(argc,argv,iap);
 
   if (BootMode == YAP_FULL_BOOT_FROM_PROLOG) {
+    YapBootDir = getenv("YAPBOOTDIR");
+    if (YapBootDir) {
 #if HAVE_STRNCAT
-    strncpy(boot_file, PL_SRC_DIR, 256);
+      strncpy(boot_file, YapBootDir, 256);
 #else
-    strcpy(boot_file, PL_SRC_DIR);
+      strcpy(boot_file, YapBootDir);
 #endif
+      strcat(boot_file, "/");
+    }
+    else {
+#if HAVE_STRNCAT
+      strncpy(boot_file, PL_SRC_DIR, 256);
+#else
+      strcpy(boot_file, PL_SRC_DIR);
+#endif
+    }
 #if HAVE_STRNCAT
     strncat(boot_file, BootFile, 256);
 #else
@@ -649,11 +661,21 @@
 	YAP_Functor fgoal;
 	YAP_Term goal, as[2];
 
+        if (YapBootDir) {
 #if HAVE_STRNCAT
-	strncpy(init_file, PL_SRC_DIR, 256);
+          strncpy(init_file, YapBootDir, 256);
 #else
-	strcpy(init_file, PL_SRC_DIR);
+          strcpy(init_file, YapBootDir);
 #endif
+          strcat(init_file, "/");
+        }
+        else {
+#if HAVE_STRNCAT
+          strncpy(init_file, PL_SRC_DIR, 256);
+#else
+	  strcpy(init_file, PL_SRC_DIR);
+#endif
+        }
 #if HAVE_STRNCAT
 	strncat(init_file, InitFile, 256);
 #else