diff -Naurp ftjam-2.5.3rc2-orig/Jambase ftjam-2.5.3rc2/Jambase
--- ftjam-2.5.3rc2-orig/Jambase	2007-06-05 08:20:19.000000000 -0600
+++ ftjam-2.5.3rc2/Jambase	2008-07-21 19:26:02.000000000 -0600
@@ -813,7 +813,7 @@ else if $(UNIX)
     LINKLIBS    ?= ;
     OPTIM       ?= -O ;
     RANLIB      ?= ranlib ;
-    YACC        ?= yacc ;
+    YACC        ?= bison -y ;
     YACCGEN     ?= .c ;
     YACCFILES   ?= y.tab ;
     YACCFLAGS   ?= -d ;
@@ -882,10 +882,10 @@ DC ?= dmd ;
     SUFLIB      ?= .a ;
     SUFOBJ      ?= .o ;
     UNDEFFLAG   ?= "-u _" ;
-    YACC        ?= ;
-    YACCGEN     ?= ;
-    YACCFILES   ?= ;
-    YACCFLAGS   ?= ;
+    YACC        ?= bison -y ;
+    YACCGEN     ?= .c ;
+    YACCFILES   ?= y.tab ;
+    YACCFLAGS   ?= -d ;
 
     HDRPATTERN =
             "^[ 	]*#[ 	]*include[ 	]*[<\"]([^\">]*)[\">].*$" ;
diff -Naurp ftjam-2.5.3rc2-orig/jambase.c ftjam-2.5.3rc2/jambase.c
--- ftjam-2.5.3rc2-orig/jambase.c	2007-06-05 08:31:08.000000000 -0600
+++ ftjam-2.5.3rc2/jambase.c	2008-07-21 19:27:55.000000000 -0600
@@ -632,7 +632,7 @@ const char *jambase[] = {
 "LINKLIBS    ?= ;\n",
 "OPTIM       ?= -O ;\n",
 "RANLIB      ?= ranlib ;\n",
-"YACC        ?= yacc ;\n",
+"YACC        ?= bison -y ;\n",
 "YACCGEN     ?= .c ;\n",
 "YACCFILES   ?= y.tab ;\n",
 "YACCFLAGS   ?= -d ;\n",
@@ -695,10 +695,10 @@ const char *jambase[] = {
 "SUFLIB      ?= .a ;\n",
 "SUFOBJ      ?= .o ;\n",
 "UNDEFFLAG   ?= \"-u _\" ;\n",
-"YACC        ?= ;\n",
-"YACCGEN     ?= ;\n",
-"YACCFILES   ?= ;\n",
-"YACCFLAGS   ?= ;\n",
+"YACC        ?= bison -y ;\n",
+"YACCGEN     ?= .c ;\n",
+"YACCFILES   ?= y.tab ;\n",
+"YACCFLAGS   ?= -d ;\n",
 "\n",
 "HDRPATTERN =\n",
 "\"^[ 	]*#[ 	]*include[ 	]*[<\\\"]([^\\\">]*)[\\\">].*$\" ;\n",