[vsipl++] PATCH: Refine vsipl++.pc generation

[Jules Bergmann]

Stefan, looks good.  Please check it in. -- Jules

Stefan Seefeld wrote:
> This patch refines the vsipl++.pc generation patch I sent out earlier.
> Options to report header / library paths and options to report compiler /
> linker flags are separated a little more clear now.
> 
> It is thus suggested that users use 'pkg-config vsipl++ --variable 
> cppflags'
> to obtain include paths, and 'pkg-config vsipl++ --variable cxxflags' to
> obtain the set of compiler flags used to compile libvsip.a (and thus,
> the flags we would suggest users to use for their own vsipl++ 
> applications).
> 
> These options should probably be documented in the quickstart guide.
> 
> Regards,
>         Stefan
>