diff --git a/ChangeLog b/ChangeLog
index 3cc375fa17..23fb0e62c3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Sun May 21 17:31:37 2000  WATANABE Hirofumi  <eban@os.rim.or.jp>
+
+	* instruby.rb: support "make install" for cross-compiling.
+
+	* ext/extmk.rb.in: ditto.
+
+Sun May 21 14:22:49 2000  WATANABE Hirofumi  <eban@os.rim.or.jp>
+
+	* Makefile.in: rename prep.rb to fake.rb.
+
+	* configure.in: ditto.
+
 Wed May 17 14:14:23 2000  Yukihiro Matsumoto  <matz@netlab.co.jp>
 
 	* re.c (rb_reg_new_1): use /m instead of /p.
diff --git a/Makefile.in b/Makefile.in
index b2dddb45e8..e4b6fd5b6e 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -125,8 +125,18 @@ test:		miniruby$(EXEEXT)
 rbconfig.rb:	miniruby$(EXEEXT)
 		@@MINIRUBY@ $(srcdir)/mkconfig.rb rbconfig.rb
 
-prep.rb:	miniruby$(EXEEXT)
-		@echo 'PLATFORM=RUBY_PLATFORM="@arch@"' > $@
+fake.rb:	miniruby$(EXEEXT)
+		@echo ' \
+		class Object; \
+		  remove_const :RUBY_PLATFORM; \
+		  RUBY_PLATFORM = "@arch@"; \
+		  if defined? PLATFORM; \
+		    remove_const :PLATFORM; \
+		    PLATFORM = "@arch@"; \
+		  end; \
+		  CROSS_COMPILING = true; \
+		end \
+		' > $@
 
 config.status:	$(srcdir)/configure
 		$(SHELL) ./config.status --recheck
diff --git a/configure.in b/configure.in
index 308371961f..c93cb4b7bc 100644
--- a/configure.in
+++ b/configure.in
@@ -688,8 +688,8 @@ if test "$fat_binary" = yes ; then
 fi
 
 if test x"$cross_compiling" = xyes; then
-  MINIRUBY='ruby -I.. -rprep'
-  PREP=prep.rb
+  MINIRUBY="ruby -I`pwd` -rfake"
+  PREP=fake.rb
 else
   MINIRUBY='./miniruby$(EXEEXT)'
   PREP=''
diff --git a/ext/extmk.rb.in b/ext/extmk.rb.in
index 90e6c71592..97152065c4 100644
--- a/ext/extmk.rb.in
+++ b/ext/extmk.rb.in
@@ -402,6 +402,9 @@ archdir = $(pkglibdir)/@arch@
     ruby_interpreter = $topdir + "/miniruby@EXEEXT@"
     ruby_interpreter.gsub!("/", "\\")
   end
+  if defined? CROSS_COMPILING
+    ruby_interpreter = "@MINIRUBY@"
+  end
 
   mfile.printf <<EOS
 TARGET = #{target}
diff --git a/instruby.rb b/instruby.rb
index 444b7e6465..da773c0825 100644
--- a/instruby.rb
+++ b/instruby.rb
@@ -66,7 +66,11 @@ if RUBY_PLATFORM =~ /-aix/
 end
 
 Dir.chdir "ext"
-system "../miniruby#{exeext} extmk.rb install #{destdir}"
+if defined? CROSS_COMPILING
+  system "#{CONFIG['MINIRUBY']} extmk.rb install #{destdir}"
+else
+  system "../miniruby#{exeext} extmk.rb install #{destdir}"
+end
 Dir.chdir CONFIG["srcdir"]
 
 Find.find("lib") do |f|