extmk.rb: check if parent is build

* ext/extmk.rb (extmake): don't build nested libraries if parent
  library isn't build.

* ext/{dl/callback,tk/tkutil}/extconf.rb: no longer need to check
  if the parent is build.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45887 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/dl/callback/extconf.rb

@@ -1,6 +1,6 @@
 require 'mkmf'
 
-if compiled?("dl")
+begin
   callbacks = (0..8).map{|i| "callback-#{i}"}.unshift("callback")
   callback_srcs = callbacks.map{|basename| "#{basename}.c"}
   callback_objs = callbacks.map{|basename| "#{basename}.o"}

ext/extmk.rb

@@ -141,6 +141,16 @@ def extmake(target)
 
   FileUtils.mkpath target unless File.directory?(target)
   begin
+    # don't build if parent library isn't build
+    parent = true
+    d = target
+    until (d = File.dirname(d)) == '.'
+      if File.exist?("#{$top_srcdir}/ext/#{d}/extconf.rb")
+        parent = (/^all:\s*install/ =~ IO.read("#{d}/Makefile") rescue false)
+        break
+      end
+    end
+
     dir = Dir.pwd
     FileUtils.mkpath target unless File.directory?(target)
     Dir.chdir target
@@ -161,8 +171,8 @@ def extmake(target)
     makefile = "./Makefile"
     static = $static
     $static = nil if noinstall = File.fnmatch?("-*", target)
-    ok = File.exist?(makefile)
-    unless $ignore
+    ok = parent && File.exist?(makefile)
+    if parent && !$ignore
       rbconfig0 = RbConfig::CONFIG
       mkconfig0 = CONFIG
       rbconfig = {
@@ -288,13 +298,15 @@ def extmake(target)
     end
   ensure
     Logging::log_close
-    unless $ignore
+    if rbconfig0
       RbConfig.module_eval {
 	remove_const(:CONFIG)
 	const_set(:CONFIG, rbconfig0)
 	remove_const(:MAKEFILE_CONFIG)
 	const_set(:MAKEFILE_CONFIG, mkconfig0)
       }
+    end
+    if mkconfig0
       MakeMakefile.class_eval {
 	remove_const(:CONFIG)
 	const_set(:CONFIG, mkconfig0)

ext/tk/tkutil/extconf.rb

@@ -1,11 +1,4 @@
 begin
-  has_tk = compiled?('tk')
-rescue NoMethodError
-  # Probably, called manually (NOT from 'extmk.rb'). Force to make Makefile.
-  has_tk = true
-end
-
-if has_tk
   require 'mkmf'
 
   have_func("rb_obj_instance_exec", "ruby.h")