Re: [PATCH] Link to -lssp when available (fixes mingw build)

["Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>]

On Wed, Dec 18, 2019 at 5:12 PM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: "Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>
> > Date: Wed, 18 Dec 2019 14:40:42 -0600
> > Cc: gdb-patches <gdb-patches@sourceware.org>a lot of
> >
> > BTW -- you mentioned a licensing issue with depending on DLLs. Doesn't
> > libstdc++ and perhaps others have the same issue? Or does mingw.org
> > link it statically?
>
> libstdc++ and libgcc DLLs indeed have the same problem.  Which is why
> I mentioned the fact that the binary of GDB 9.0.90 produced by the
> MinGW build had dependencies on these two.  I solved that locally by
> linking with "CXX='g++ -static-libstdc++ -static-libgcc'", but I
> thought Pedro once said these dependencies shouldn't happen, and I
> still hope we could understand why they suddenly appeared.

Hm, I wonder why Pedro said that. GDB uses good amounts of the C++
standard library, so I would totally expect libstdc++ to appear. I
don't really know what libgcc is used for.

> > My msys2/mingw64 gcc depends on these DLLs outside of SYSTEM32:
> >         libpython3.8.dll => /mingw64/bin/libpython3.8.dll (0x70840000)
> >         libwinpthread-1.dll => /mingw64/bin/libwinpthread-1.dll (0x64940000)
> >         libgcc_s_seh-1.dll => /mingw64/bin/libgcc_s_seh-1.dll (0x61440000)
> >         libstdc++-6.dll => /mingw64/bin/libstdc++-6.dll (0x6fc40000)
>
> In general, any binary that depends on some DLLs and comes with those
> DLLs needs to be accompanied by the sources of all the DLLs, to be
> compatible with GPL.  In the above list, all the DLLs except Python
> are part of GCC, so as long as the GCC sources are available, the
> MinGW64 folks are okay.  I don't know how they deal with the problem
> of providing the Python sources, though.
>
> For the binaries I produce, I always try to link statically against
> DLLs that come from GCC, because I don't want to distribute the
> humongous GCC sources, and I don't want to provide a binary
> distribution that is not self-contained (i.e. without those
> problematic DLLs).

Is libwinpthread-1 part of GCC? I would have thought that's part of
mingw's runtime (how do you deal with that yourself?)

Thanks for the explanation!

Christian