diff -ur celorig/Jamrules.in cel/Jamrules.in
--- celorig/Jamrules.in	2003-02-24 18:13:13.000000000 +0100
+++ cel/Jamrules.in	2003-05-03 14:41:11.000000000 +0200
@@ -6,6 +6,7 @@
 PYTHON_LIBS = "@PYTHON_LIBS@" ;
 PYTHON_CFLAGS = "@PYTHON_CFLAGS@" ;
 
+Cc = @CC@ ;
 C++ = @CXX@ ;
 LINK = $(C++) ;
 
@@ -13,13 +14,13 @@
 C++FLAGS += $(CRYSTAL_C++FLAGS) ;
 LINKLIBS += $(CRYSTAL_LIBS) ;
 
-prefix = "@prefix@" ;
-exec_prefix = "@exec_prefix@" ;
-libdir = "@libdir@" ;
-plugindir = "@libdir@/cel" ;
-csconfdir = "@bindir@" ;
-bindir = "@bindir@" ;
-includedir = "@includedir@" ;
+prefix ?= "@prefix@" ;
+exec_prefix ?= "@exec_prefix@" ;
+libdir ?= "@libdir@" ;
+plugindir ?= "@libdir@/cel" ;
+csconfdir ?= "@bindir@" ;
+bindir ?= "@bindir@" ;
+includedir ?= "@includedir@" ;
 
 C++FLAGS += "-DLIBDIR='\"$(plugindir)/\"'" ;