There are several osl APIs that relate to symbols within shared libraries and
that require symbol addresses to be passed as void*.

Frequently these APIs need to be used with function symbols, so clients need to
convert parameters or results between void* and function pointers. Such
conversions are illegal in C++ (and potentially even in C).

Even though compilers can be made to do the required conversion, this forces use
of C-Style casts and produces warnings at higher warning levels. There may even
exit platforms, where this ceases to work at all.

This portability issue should be encapsulated in sal, to shield client code from
that problem and allow a global reduction of warnings. All osl functions that
work on symbol adresses should provide two signatures, one of which supports
function pointers.

Suggested header additions:

osl/module.h:
    typedef void (*oslGenericFunction)(void);

    oslGenericFunction SAL_CALL 
    osl_getFunctionSymbol(oslModule Module, rtl_uString *strSymbolName);

    sal_Bool SAL_CALL 
    osl_getModuleURLFromFunctionAddress( oslGenericFunction pf, 
                                         rtl_uString **pustrURL );

osl/module.hxx:	
    oslGenericFunction SAL_CALL osl::Module::
    getFunctionSymbol( const ::rtl::OUString& strSymbolName);

    static sal_Bool SAL_CALL osl::Module::
    getUrlFromAddress(oslGenericFunction addr, ::rtl::OUString & libraryUrl);

Note: The inconsistency in the spelling of URL/Url was copied from existing APIs.