rbinstall.rb: install ext only when it's configured [Bug #18414]

common.mk

@@ -176,6 +176,7 @@ GOLFPRELUDES  = {$(srcdir)}golf_prelude.c
 
 SCRIPT_ARGS   =	--dest-dir="$(DESTDIR)" \
 		--extout="$(EXTOUT)" \
+		--ext-build-dir="./ext" \
 		--mflags="$(MFLAGS)" \
 		--make-flags="$(MAKEFLAGS)"
 EXTMK_ARGS    =	$(SCRIPT_ARGS) --extension $(EXTS) --extstatic $(EXTSTATIC) \

tool/rbinstall.rb

@@ -61,6 +61,7 @@ def parse_args(argv = ARGV)
   opt.on('-n', '--dry-run') {$dryrun = true}
   opt.on('--dest-dir=DIR') {|dir| $destdir = dir}
   opt.on('--extout=DIR') {|dir| $extout = (dir unless dir.empty?)}
+  opt.on('--ext-build-dir=DIR') {|v| $ext_build_dir = v }
   opt.on('--make=COMMAND') {|make| $make = make}
   opt.on('--mantype=MAN') {|man| $mantype = man}
   opt.on('--make-flags=FLAGS', '--mflags', Shellwords) do |v|
@@ -151,6 +152,9 @@ def parse_args(argv = ARGV)
 
   $dir_mode ||= $prog_mode | 0700
   $script_mode ||= $prog_mode
+  if $ext_build_dir.nil?
+    raise OptionParser::MissingArgument.new("--ext-build-dir=DIR")
+  end
 end
 
 $install_procs = Hash.new {[]}
@@ -729,6 +733,16 @@ module RbInstall
         (ruby_libraries + built_libraries).sort
       end
 
+      def skip_install?(files)
+        case type
+        when "ext"
+          # install ext only when it's configured
+          !File.exist?("#{$ext_build_dir}/#{relative_base}/Makefile")
+        when "lib"
+          files.empty?
+        end
+      end
+
       private
       def type
         /\/(ext|lib)?\/.*?\z/ =~ @base_dir
@@ -966,6 +980,9 @@ def install_default_gem(dir, srcdir, bindir)
     spec = load_gemspec(src)
     file_collector = RbInstall::Specs::FileCollector.new(src)
     files = file_collector.collect
+    if file_collector.skip_install?(files)
+      next
+    end
     spec.files = files
     spec
   }