support cross-compilation.

On cross-compilation, compiled binary can no be created because
compiled binary should be created by same interpreter (on cross-
compilation, host ruby is used to build ruby (BASERUBY)).
So that cross-compilation system loads required scripts in text.
It is same as miniruby.

builtin.c

@@ -3,6 +3,13 @@
 #include "iseq.h"
 #include "builtin.h"
 
+#if CROSS_COMPILING
+
+#define INCLUDED_BY_BUILTIN_C 1
+#include "mini_builtin.c"
+
+#else
+
 #include "builtin_binary.inc"
 
 static const unsigned char*
@@ -36,6 +43,8 @@ rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin
     rb_iseq_eval(iseq);
 }
 
+#endif
+
 void
 Init_builtin(void)
 {

common.mk

@@ -1115,7 +1115,7 @@ preludes: {$(srcdir)}golf_prelude.c
 	$(Q) $(BASERUBY) $(srcdir)/tool/mk_builtin_loader.rb $<
 
 builtin_binary.inc: $(PREP) $(BUILTIN_RB_SRCS) $(srcdir)/tool/mk_builtin_binary.rb
-	$(Q) $(MINIRUBY) $(srcdir)/tool/mk_builtin_binary.rb
+	$(Q) $(MINIRUBY) $(srcdir)/tool/mk_builtin_binary.rb --cross=$(CROSS_COMPILING)
 
 $(BUILTIN_RB_INCS): $(top_srcdir)/tool/mk_builtin_loader.rb
 

configure.ac

@@ -3053,6 +3053,7 @@ AS_IF([test x"$cross_compiling" = xyes], [
   XRUBY='$(MINIRUBY)'
   TEST_RUNNABLE=no
   CROSS_COMPILING=yes
+  AC_DEFINE(CROSS_COMPILING, 1)
 ], [
   MINIRUBY='./miniruby$(EXEEXT) -I$(srcdir)/lib -I.'
   MINIRUBY="$MINIRUBY"' -I$(EXTOUT)/common'

mini_builtin.c

@@ -2,11 +2,15 @@
 #include "vm_core.h"
 #include "iseq.h"
 #include "builtin.h"
+
 #include "miniprelude.c"
 
 // included from miniinit.c
 
+#ifndef INCLUDED_BY_BUILTIN_C
 static struct st_table *loaded_builtin_table;
+#endif
+
 rb_ast_t *rb_builtin_ast(const char *feature_name, VALUE *name_str);
 
 static const rb_iseq_t *
@@ -26,8 +30,10 @@ builtin_iseq_load(const char *feature_name, const struct rb_builtin_function *ta
         rb_io_write(rb_stdout, rb_iseq_disasm((const rb_iseq_t *)iseq));
     }
 
+#ifndef INCLUDED_BY_BUILTIN_C
     st_insert(loaded_builtin_table, (st_data_t)feature_name, (st_data_t)iseq);
     rb_gc_register_mark_object((VALUE)iseq);
+#endif
 
     return iseq;
 }
@@ -39,6 +45,8 @@ rb_load_with_builtin_functions(const char *feature_name, const struct rb_builtin
     rb_iseq_eval(iseq);
 }
 
+#ifndef INCLUDED_BY_BUILTIN_C
+
 static int
 each_builtin_i(st_data_t key, st_data_t val, st_data_t dmy)
 {
@@ -70,3 +78,4 @@ Init_builtin_features(void)
     // register for ruby
     builtin_iseq_load("gem_prelude", NULL);
 }
+#endif

tool/mk_builtin_binary.rb

@@ -11,11 +11,6 @@ def dump_bin iseq
   print "\n"
 end
 
-ary = []
-RubyVM::each_builtin{|feature, iseq|
-  ary << [feature, iseq]
-}
-
 $stdout = open('builtin_binary.inc', 'wb')
 
 puts <<H
@@ -25,17 +20,25 @@ puts <<H
 
 H
 
-ary.each{|feature, iseq|
-  print "\n""static const unsigned char #{feature}_bin[] = {"
+if !ARGV.grep('--cross=yes').empty?
+  # do nothing
+else
+  ary = []
+  RubyVM::each_builtin{|feature, iseq|
+    ary << [feature, iseq]
+  }
+
+  ary.each{|feature, iseq|
+    print "\n""static const unsigned char #{feature}_bin[] = {"
     dump_bin(iseq)
+    puts "};"
+  }
+
+  print "\n""static const struct builtin_binary builtin_binary[] = {\n"
+  ary.each{|feature, iseq|
+    puts "  {#{feature.dump}, #{feature}_bin, sizeof(#{feature}_bin)},"
+  }
+  puts "  {NULL}," # dummy sentry
   puts "};"
-}
-
-print "\n""static const struct builtin_binary builtin_binary[] = {\n"
-ary.each{|feature, iseq|
-  puts "  {#{feature.dump}, #{feature}_bin, sizeof(#{feature}_bin)},"
-}
-puts "  {NULL}," # dummy sentry
-puts "};"
-
-puts "#define BUILTIN_BINARY_SIZE #{ary.size}"
+  puts "#define BUILTIN_BINARY_SIZE #{ary.size}"
+end