[ruby-dev:30947] Problem in installing the last Ruby 1.9

Hi,

This morning I had an error during the installation of Ruby 1.9
(yesterday it was working fine):
~/src/ruby% sudo make install
./miniruby  ./instruby.rb --dest-dir="" --extout=".ext" --make="make"
--mflags="" --make-flags="" --installed-list .installed.list
--mantype="doc"
installing binary commands
installing command scripts
installing library scripts
installing headers
/Users/vincent/src/ruby/lib/fileutils.rb:1256:in `initialize': No such
file or directory - /usr/local/include/ruby-1.9/ruby/defines.h
(Errno::ENOENT)
        from /Users/vincent/src/ruby/lib/fileutils.rb:1256:in `open'
        from /Users/vincent/src/ruby/lib/fileutils.rb:1256:in `block
in copy_file'
        from /Users/vincent/src/ruby/lib/fileutils.rb:1255:in `open'
        from /Users/vincent/src/ruby/lib/fileutils.rb:1255:in `copy_file'
        from /Users/vincent/src/ruby/lib/fileutils.rb:462:in `copy_file'
        from /Users/vincent/src/ruby/lib/fileutils.rb:838:in `block in install'
        from /Users/vincent/src/ruby/lib/fileutils.rb:1389:in `block
in fu_each_src_dest'
        from /Users/vincent/src/ruby/lib/fileutils.rb:1405:in
`fu_each_src_dest0'
         ... 9 levels...
        from ./instruby.rb:356:in `each'
        from ./instruby.rb:356:in `block in <main>'
        from ./instruby.rb:355:in `each'
        from ./instruby.rb:355:in `<main>'
make: *** [do-install-nodoc] Error 1

The file can't be created because the destination directory
(/usr/local/include/ruby-1.9/ruby) does not exist (it has not been
created).

Cheers,
Vincent Isambart