diff --git a/Makefile.in b/Makefile.in
index 9c8dbced0f..2afea66b8b 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -246,9 +246,6 @@ $(LIBRUBY_SO):
 		@-$(MINIRUBY) -e 'ARGV.each{|link| File.delete link rescue nil; \
 						  File.symlink "$(LIBRUBY_SO)", link}' \
 				$(LIBRUBY_ALIASES) || true
-$(arch)-fake.rb: config.status $(srcdir)/template/fake.rb.in
-		@./config.status --file=$@:$(srcdir)/template/fake.rb.in
-		@chmod +x $@
 
 ruby_pc = @ruby_pc@
 $(ruby_pc):
diff --git a/common.mk b/common.mk
index b84de9c519..7949e61f47 100644
--- a/common.mk
+++ b/common.mk
@@ -549,6 +549,11 @@ fake: $(CROSS_COMPILING)-fake
 yes-fake: $(arch)-fake.rb $(RBCONFIG) PHONY
 no-fake: PHONY
 
+$(arch)-fake.rb: $(RBCONFIG) $(srcdir)/template/fake.rb.in $(srcdir)/tool/expand-config.rb rbconfig.rb
+	@$(BOOTSTRAPRUBY) $(srcdir)/tool/expand-config.rb \
+		-output=$@ -mode=$(INSTALL_PROG_MODE) -expand -config=rbconfig.rb \
+		srcdir="$(srcdir)" BASERUBY="$(BASERUBY)" $(srcdir)/template/fake.rb.in
+
 btest: $(TEST_RUNNABLE)-btest
 no-btest: PHONY
 yes-btest: fake miniruby$(EXEEXT) PHONY
diff --git a/template/fake.rb.in b/template/fake.rb.in
index 8e461c57a4..0363b10e83 100644
--- a/template/fake.rb.in
+++ b/template/fake.rb.in
@@ -19,11 +19,7 @@ class Object
   RUBY_DESCRIPTION = "ruby #{RUBY_VERSION} (#{RUBY_RELEASE_DATE}) [#{RUBY_PLATFORM}]"
 end
 builddir = File.dirname(__FILE__)
-top_srcdir = "@abs_top_srcdir@"
-if /mingw/ =~ RUBY_PLATFORM
-  # convert MSYS path to Windows path
-  top_srcdir.sub!(/\A\/([a-z])\//, '\\1:/')
-end
+top_srcdir = File.join(builddir, "@srcdir@")
 $:.unshift(File.expand_path(builddir))
 fake = File.join(top_srcdir, "tool/fake.rb")
 eval(File.read(fake), nil, fake)
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 7d0fbf1b1b..11bcee6e6f 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -1056,24 +1056,6 @@ $(RCFILES): $(RBCONFIG) $(srcdir)/revision.h $(srcdir)/win32/resource.rb
 			-so_name=$(RUBY_SO_NAME) \
 			. $(icondirs) $(win_srcdir)
 
-$(arch)-fake.rb: $(MKFILES) $(srcdir)/version.h
-	@echo Creating <<$@
-class Object
-  remove_const :CROSS_COMPILING if defined?(CROSS_COMPILING)
-  CROSS_COMPILING = RUBY_PLATFORM
-  remove_const :RUBY_PLATFORM
-  remove_const :RUBY_VERSION
-  remove_const :RUBY_DESCRIPTION if defined?(RUBY_DESCRIPTION)
-  RUBY_PLATFORM = "$(arch)"
-  RUBY_VERSION = $(RUBY_PROGRAM_VERSION)
-  RUBY_DESCRIPTION = "ruby #{RUBY_VERSION} (" $(RUBY_RELEASE_DATE) ") [#{RUBY_PLATFORM}]"
-end
-class File
-  remove_const :ALT_SEPARATOR
-  ALT_SEPARATOR = "\\"
-end
-<<KEEP
-
 $(ruby_pc): $(RBCONFIG)
 	@$(BOOTSTRAPRUBY) $(srcdir)/tool/expand-config.rb \
 		-output=$@ -mode=$(INSTALL_DATA_MODE) -config=rbconfig.rb \