diff --git a/ext/io/console/depend b/ext/io/console/depend
index 73638fe7..e7555961 100644
--- a/ext/io/console/depend
+++ b/ext/io/console/depend
@@ -1,15 +1,3 @@
-win32_vk.inc: win32_vk.list $(srcdir)/extract-vk.rb
-
-.list.inc:
-	( \
-	$(RUBY) $(srcdir)/extract-vk.rb $< && \
-	gperf --ignore-case -L ANSI-C -E -C -P -p -j1 -i 1 -g -o -t -K ofs -N console_win32_vk -k* $< \
-	| sed -f $(top_srcdir)/tool/gperf.sed \
-	) > $(@F)
-
-.SUFFIXES: .chksum .list .inc
-
-.list.chksum:
-	@$(RUBY) -I$(top_srcdir)/tool -rchecksum \
-	    -e "Checksum.update(ARGV) {|k|k.copy(k.target) rescue k.make(k.target)}" \
-	    -- --make=$(MAKE) -I$(srcdir) $(<F) $(@F:.chksum=.inc)
+# AUTOGENERATED DEPENDENCIES START
+console.o: console.c
+# AUTOGENERATED DEPENDENCIES END
diff --git a/ext/io/console/extconf.rb b/ext/io/console/extconf.rb
index d10bdcfe..65d36057 100644
--- a/ext/io/console/extconf.rb
+++ b/ext/io/console/extconf.rb
@@ -52,8 +52,22 @@
   have_const("RB_WARN_CATEGORY_DEPRECATED")
   win32 or have_func("ttyname_r") or have_func("ttyname")
   have_func("rb_prepend_module") # not exported by TruffleRuby
+  vk_tool = find_executable("gperf")
   create_makefile("io/console") {|conf|
-    conf << "\n""VK_HEADER = #{vk_header}\n"
+    conf << "###\n" "all: # the default target\n"
+    if vk_header
+      conf << <<~MK
+        VK_HEADER = #{vk_header}
+        console.#$OBJEXT: $(VK_HEADER)
+      MK
+    end
+    if vk_tool
+      unless conf.any? {|c| /^ *top_srcdir *=/.match?(c)}
+        conf << "top_srcdir = $(srcdir)/../../..\n"
+      end
+      conf.concat(depend_rules(File.read("#$srcdir/win32_vk.mk")))
+    end
+    conf
   }
 when nil
   File.write("Makefile", dummy_makefile($srcdir).join(""))
diff --git a/ext/io/console/extract-vk.rb b/ext/io/console/extract-vk.rb
index 387d5b38..94c3bac7 100644
--- a/ext/io/console/extract-vk.rb
+++ b/ext/io/console/extract-vk.rb
@@ -1,7 +1,18 @@
 code = [+""]
-ARGF.read.scan(/^\w+,\s*\KVK_\w+/) do |n|
+source = File.read(ARGV.shift)
+source.scan(/^\w+,\s*\KVK_\w+/) do |n|
   puts("#ifndef #{n}\n# define #{n} UNDEFINED_VK\n#endif")
   code << +"" if n.size + code.last.size > 60
   code.last << " x(#{n})z"
 end
 puts ["#define EACH_VK(x,z)", code].join(" \\\n    "), ""
+IO.popen(["gperf", *ARGV], "r+") do |f|
+  w = Thread.start {
+    f.puts source
+    f.close_write
+  }
+  puts f.read.sub(/^\w*hash .*\{(?m:.*?)\n\}/) {
+    $&.sub!(" hval = ", " hval = (unsigned int)")
+  }
+  w.join
+end
diff --git a/ext/io/console/win32_vk.mk b/ext/io/console/win32_vk.mk
new file mode 100644
index 00000000..97757a05
--- /dev/null
+++ b/ext/io/console/win32_vk.mk
@@ -0,0 +1,13 @@
+win32_vk.inc: win32_vk.list $(srcdir)/extract-vk.rb
+
+.list.inc:
+	$(Q)$(RUBY) $(srcdir)/extract-vk.rb $< \
+	    --ignore-case -L ANSI-C -E -C -P -p -j1 -i 1 -g -o -t -K ofs -N console_win32_vk -k* \
+	    > $(@F)
+
+.SUFFIXES: .chksum .list .inc
+
+.list.chksum:
+	@$(RUBY) -I$(top_srcdir)/tool -rchecksum \
+	    -e "Checksum.update(ARGV) {|k|k.copy(k.target) rescue k.make(k.target)}" \
+	    -- --make=$(MAKE) -I$(srcdir) $(<F) $(@F:.chksum=.inc)
diff --git a/tool/gperf.sed b/tool/gperf.sed
deleted file mode 100644
index 9550a522..00000000
--- a/tool/gperf.sed
+++ /dev/null
@@ -1,4 +0,0 @@
-/^[a-zA-Z_0-9]*hash/,/^}/{
-  s/ hval = / hval = (unsigned int)/
-  s/ return / return (unsigned int)/
-}