Incremental improvement to the darwin toolset.
* Set the proper suffix for shared libraries
* Added C and C++ compile options used in v1:
-Wno-long-double, -no-cpp-precomp, and -fcoalesce-templates
* Converted the link.dll rule to use the bundled libtool
* Added support for linking to frameworks
Patch from Christopher Currie.
[SVN r20695]
Vladimir Prus