handle.c: suppress a warning

* ext/fiddle/handle.c (rb_fiddle_handle_initialize): suppress an
  unused-but-set-variable warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48912 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
fiddle: fix build failures

* ext/fiddle/depend (build-libffi): get rid of eventually empty
  target for nmake.

* ext/fiddle/extconf.rb: omit stuffs for libffi unless bundled
  libffi is found and used.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48913 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
handle.c: suppress warnings

* ext/fiddle/handle.c (CHECK_DLERROR): suppress warnings for using
  the result of an assignment as a condition without parentheses.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48914 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
fiddle: do not disturb other checks

* ext/fiddle/extconf.rb: add the local ffi library and header just
  before create_makefile, not to disturb other checks.
  also prepend the extension path name to the local library name
  for static linked ext.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48915 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
fiddle: modversion may be unavailable

* ext/fiddle/extconf.rb: modversion may be unavailable.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48916 b2dd03c8-39d4-4d8f-98ff-823fe69b080e