diff -ru a//defaults.make b//defaults.make
--- a//defaults.make	2010-05-11 18:50:35.000000000 +0300
+++ b//defaults.make	2010-06-07 21:24:55.000000000 +0300
@@ -31,7 +31,7 @@
 STACKDIRECTION ?= 1
 CROSS_CHICKEN ?= 0
 
-ifeq ($(ARCH),x86-64)
+ifeq ($(zARCH),x86-64)
 NURSERY ?= (256*1024)
 else
 NURSERY ?= (128*1024)
@@ -272,10 +272,10 @@
 POSIXFILE ?= posixunix
 CHICKEN_CONFIG_H = chicken-config.h
 
-ifneq ($(ARCH),)
+ifneq ($(zARCH),)
 HACKED_APPLY ?= 1
-APPLY_HACK_SRC ?= apply-hack.$(ARCH)$(ASM)
-APPLY_HACK_OBJECT ?= apply-hack.$(ARCH)$(O)
+APPLY_HACK_SRC ?= apply-hack.$(zARCH)$(ASM)
+APPLY_HACK_OBJECT ?= apply-hack.$(zARCH)$(O)
 endif
 
 ifeq ($(HACKED_APPLY),)
diff -ru a//Makefile.bsd b//Makefile.bsd
--- a//Makefile.bsd	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.bsd	2010-06-07 21:24:25.000000000 +0300
@@ -33,7 +33,7 @@
 
 # platform configuration
 
-ARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
+zARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
 
 # options
 
diff -ru a//Makefile.cross-linux-mingw b//Makefile.cross-linux-mingw
--- a//Makefile.cross-linux-mingw	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.cross-linux-mingw	2010-06-07 21:23:02.000000000 +0300
@@ -34,7 +34,7 @@
 # platform configuration
 
 DLLSINPATH = 1
-ARCH ?= x86
+zARCH ?= x86
 HACKED_APPLY = 1
 WINDOWS = 1
 
@@ -72,7 +72,7 @@
 
 # special files
 
-APPLY_HACK_OBJECT = apply-hack.$(ARCH)$(O)
+APPLY_HACK_OBJECT = apply-hack.$(zARCH)$(O)
 POSIXFILE = posixwin
 
 # select default and internal settings
diff -ru a//Makefile.cygwin b//Makefile.cygwin
--- a//Makefile.cygwin	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.cygwin	2010-06-07 21:24:07.000000000 +0300
@@ -33,7 +33,7 @@
 
 # platform configuration
 
-ARCH ?= x86
+zARCH ?= x86
 HACKED_APPLY ?= 1
 DLLSINPATH = 1
 
@@ -76,7 +76,7 @@
 # special files
 
 CHICKEN_CONFIG_H = chicken-config.h
-APPLY_HACK_OBJECT = apply-hack.$(ARCH)$(O)
+APPLY_HACK_OBJECT = apply-hack.$(zARCH)$(O)
 
 # select default and internal settings
 
diff -ru a//Makefile.linux b//Makefile.linux
--- a//Makefile.linux	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.linux	2010-06-07 21:25:31.000000000 +0300
@@ -33,7 +33,7 @@
 
 # platform configuration
 
-ARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
+zARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
 
 # options
 
diff -ru a//Makefile.macosx b//Makefile.macosx
--- a//Makefile.macosx	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.macosx	2010-06-07 21:23:51.000000000 +0300
@@ -33,7 +33,7 @@
 
 # platform configuration
 
-ARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
+zARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
 
 # commands
 
@@ -64,19 +64,19 @@
 # special files
 
 CHICKEN_CONFIG_H = chicken-config.h
-APPLY_HACK_OBJECT = apply-hack.$(ARCH)$(O)
+APPLY_HACK_OBJECT = apply-hack.$(zARCH)$(O)
 HACKED_APPLY ?= 1
 
 # architectures
 
-ifeq ($(ARCH),x86-64)
+ifeq ($(zARCH),x86-64)
 C_COMPILER_OPTIONS += -m64
 LINKER_OPTIONS += -m64
 # Avoid bus error in install_name_tool
 LINKER_LINK_SHARED_DLOADABLE_OPTIONS += -Wl,-headerpad -Wl,128
 else
 
-ifeq ($(ARCH),universal)
+ifeq ($(zARCH),universal)
 C_COMPILER_OPTIONS += -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk
 LINKER_OPTIONS += -arch ppc -arch i386 -isysroot /Developer/SDKs/MacOSX10.4u.sdk
 endif
@@ -126,7 +126,7 @@
 endif
 	cat chicken-defaults.h >>$@
 
-ifeq ($(ARCH),universal)
+ifeq ($(zARCH),universal)
 ifneq ($(HACKED_APPLY),)
 # We undefine HACKED_APPLY in order to override rules.make
 # with our own build rules.
diff -ru a//Makefile.mingw b//Makefile.mingw
--- a//Makefile.mingw	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.mingw	2010-06-07 21:25:59.000000000 +0300
@@ -36,12 +36,12 @@
 # platform configuration
 
 DLLSINPATH = 1
-ARCH ?= x86
+zARCH ?= x86
 WINDOWS = 1
 WINDOWS_SHELL = 1
 UNAME_SYS = MinGW
 
-ifeq ($(ARCH),x86)
+ifeq ($(zARCH),x86)
 HACKED_APPLY ?= 1
 else
 HACKED_APPLY =
@@ -79,7 +79,7 @@
 # special files
 
 CHICKEN_CONFIG_H = chicken-config.h
-APPLY_HACK_OBJECT = apply-hack.$(ARCH)$(O)
+APPLY_HACK_OBJECT = apply-hack.$(zARCH)$(O)
 POSIXFILE = posixwin
 
 # select default and internal settings
diff -ru a//Makefile.mingw-msys b//Makefile.mingw-msys
--- a//Makefile.mingw-msys	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.mingw-msys	2010-06-07 21:26:33.000000000 +0300
@@ -34,8 +34,8 @@
 # platform configuration
 
 DLLSINPATH = 1
-ARCH ?= x86
-ifeq ($(ARCH),x86)
+zARCH ?= x86
+ifeq ($(zARCH),x86)
 HACKED_APPLY ?= 1
 else
 HACKED_APPLY =
@@ -79,7 +79,7 @@
 # special files
 
 CHICKEN_CONFIG_H = chicken-config.h
-APPLY_HACK_OBJECT = apply-hack.$(ARCH)$(O)
+APPLY_HACK_OBJECT = apply-hack.$(zARCH)$(O)
 POSIXFILE = posixwin
 
 # select default and internal settings
diff -ru a//Makefile.solaris b//Makefile.solaris
--- a//Makefile.solaris	2010-05-11 18:50:34.000000000 +0300
+++ b//Makefile.solaris	2010-06-07 21:25:45.000000000 +0300
@@ -33,7 +33,7 @@
 
 # platform configuration
 
-ARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
+zARCH ?= $(shell sh $(SRCDIR)/config-arch.sh)
 
 # options
 
diff -ru a//rules.make b//rules.make
--- a//rules.make	2010-05-11 18:50:36.000000000 +0300
+++ b//rules.make	2010-06-07 21:26:10.000000000 +0300
@@ -453,7 +453,7 @@
 # assembler objects
 
 ifneq ($(HACKED_APPLY),)
-$(APPLY_HACK_OBJECT): $(SRCDIR)apply-hack.$(ARCH)$(ASM)
+$(APPLY_HACK_OBJECT): $(SRCDIR)apply-hack.$(zARCH)$(ASM)
 	$(ASSEMBLER) $(ASSEMBLER_OPTIONS) $(ASSEMBLER_COMPILE_OPTION) $< $(ASSEMBLER_OUTPUT)
 endif